NCERT Solutions for Class 4 Maths Mela Chapter 06 Measuring Length

Question 1. Look at the picture. What are the students measuring? Put a tick mark (✓) if you find it being measured. a) Length b) Height c) Weight d) Depth e) Breadth f) Temperature
Answer: (a) Length ✓ (b) Height ✓ (e) Breadth ✓
In simple words: The students are measuring how long, tall, and wide things are. They use checkmarks to show which types of measuring they are doing.

Exam Tip: Look at what tools are being used in the picture - if it is a measuring tape held vertically, that shows height; if held horizontally, that shows length or breadth.

Question 2. What is being used to measure the height? What other tools can be used to measure height?
Answer: A measuring tape is being used in the picture to take the height. Other tools you can use include a ruler, a metre stick, a height chart, a stadiometer, or a wall marking.
In simple words: The measuring tape is the tool shown. You can also use many other things like a ruler or a marking on the wall to find out how tall something is.

Exam Tip: Remember that any tool with clear markings for metres and centimetres works for measuring height - the key is having accurate marks on the tool.

Question 3. Recall in Grade 3 you studied that lengths are measured in metres. Check and fill in the blanks whether the following are correct/incorrect for your classroom. a) The height of most of the students in my grade is more than a metre. b) The length of my arm is less than a metre. c) The height of the door of the grade is less than a metre. d) The breadth of the blackboard is more than a metre.
Answer: (a) Correct (b) Correct (c) Incorrect - doors are typically more than a metre high (d) Correct
In simple words: Most kids are taller than one metre, arms are shorter than one metre, doors are taller than one metre, and blackboards are wider than one metre.

Exam Tip: Think of a one-metre rope or stick - use this as a reference when deciding if something is more or less than one metre.

Question 4. Walk, Jump, and Crawl on 1, 5 and 10 m line. Draw lines of 1m, 5m, and 10m on the floor of the classroom or outside in the playground. How will you make these lines? Think and share with your friends. Walk, jump, and crawl on the lines.
Answer: First, place one metre rope straight on the ground to make a 1 metre line. Then, to make a 5 metre line, lay five 1 metre ropes one after another in a straight line. To make a 10 metre line, place ten 1 metre ropes together in a straight line. If you don't have enough ropes, you can use a mix of half metre and quarter metre ropes together. After drawing the lines, walk, jump, and crawl on each one. This activity helps you understand how long 1 m, 5 m, and 10 m really are and compare their lengths easily.
In simple words: Connect ropes end to end to make lines of different lengths. Then move across each line to feel how long each distance is.

Exam Tip: Make sure the ropes are laid straight and connected tightly - any gaps will make your measurement wrong.

Question 5. Long Jump. Each child can participate in a long jump competition. How far have your friends jumped? Measure as accurately as possible using a combination of ropes. Who jumped the longest distance? Fill the following table.
Answer:

Exam Tip: Always mark the starting point clearly and measure from that exact spot to where the jumper lands - this makes your measurement correct.

Question 6. Estimate how long and broad is your classroom. Measure and check.
Answer: First, I guessed the length and breadth of my classroom by looking at it. I thought the length was about 8 metres and the breadth was about 6 metres. Then I measured the classroom using a measuring tape and metre rope. After measuring, I found that the real length was 9 metres and the real breadth was 6 metres. My first guess was very close to the real measurement.
In simple words: Look at the classroom and make a guess. Then measure with a tape to find the real size. Compare your guess with what you measured.

Exam Tip: When estimating, use a known distance like a 1 metre rope and compare it against the room - this helps you make a better guess.

Question 7. Look at the pictures carefully and answer the questions. What is the length of one bus in metres? What is the length of one cricket bat in metres?
Answer: One bus is roughly 15 metres long. One cricket bat is roughly 0.85 to 0.9 metres long.
In simple words: A bus is much longer than a cricket bat. A bus is about 15 metres, and a bat is less than 1 metre.

Exam Tip: Use the scale given in the picture to compare the lengths - this helps you find the right answer without measuring the real objects.

Question 8. How many buses would be equal to the length of two blue whales?
Answer: A blue whale is about 30 metres long. Two blue whales would be 60 metres in total. To find how many buses: 60 ÷ 15 = 4 buses.
In simple words: Two whales together are as long as 4 buses lined up end to end.

Exam Tip: Always multiply the length of one whale by the number of whales first, then divide by the bus length - this keeps your calculation in the right order.

Question 9. How many cricket bats will be needed to measure one whale?
Answer: One cricket bat is about 0.9 metres long. One whale is 30 metres long. To find how many bats: 30 ÷ 0.9 = 33 to 34 bats (roughly).
In simple words: You would need about 33 or 34 cricket bats lined up to equal the length of one whale.

Exam Tip: When dividing by a decimal, it is fine to round your answer to a whole number since we are counting bats.

Question 10. If two ostriches stand one above another, their height will be equal to the height of ______________.
Answer: Ostriches are around 2.5 metres tall and giraffes are about 5 metres tall. If two ostriches stand one above another, their combined height will equal the height of "a giraffe".
In simple words: Two ostriches stacked on top of each other will be as tall as one giraffe.

Exam Tip: Add the heights together - if each ostrich is 2.5 m, then 2.5 + 2.5 = 5 m, which is a giraffe's height.

Question 11. How many crocodiles will be equal to the length of a blue whale?
Answer: Crocodile length is 6 metres (from the image). Whale length is 30 metres. Number of crocodiles = 30 ÷ 6 = 5 crocodiles.
In simple words: Five crocodiles laid end to end would be as long as one blue whale.

Exam Tip: Always divide the larger length by the smaller length to find how many of the smaller object fit into the larger one.

Question 12. Compare the metre rope with the measuring tape used by a tailor. Is the length of both the same or different?
Answer: When you compare a metre rope with a tailor's measuring tape, they are the same length - both are 1 metre or 100 centimetres. However, the measuring tape has more detailed markings that help take more precise measurements.
In simple words: Both are 1 metre long, but the tape has better marks to help measure smaller sizes.

Exam Tip: The measuring tape's fine markings make it better for measuring small objects like clothing, while a rope is better for measuring large distances.

Question 13. Observe the measuring tape carefully. What do you notice?
Answer: Looking at the measuring tape carefully, you notice it has clear markings for each centimetre and sometimes smaller markings for millimetres. These marks help you measure with much greater precision than a plain rope.
In simple words: The tape has many small lines and numbers. Each line marks 1 centimetre, and the tiny lines mark even smaller parts.

Exam Tip: Count the spaces between the numbers - there are always 10 small divisions, with each division being 1 millimetre.

Question 14. Discuss how these marks help us measure clearly.
Answer: These marks help us measure clearly because they give us steady, standard units that everyone agrees on. This allows us to be exact when measuring small things like Chutki's growing plant. Without the marks, we would just guess and get different answers each time.
In simple words: The marks let us be very exact. Everyone reads the same marks the same way, so everyone gets the same answer.

Exam Tip: Always read the mark where the object ends, not where it starts - this gives you the true length of the object.

Question 15. Measure each object using a scale.
Answer: To measure each object, place the scale next to the object so that the zero mark lines up with one end. Read the number where the other end of the object touches the scale. This number is the length in centimetres. The objects shown (eraser, pencil, comb, and green prism) will have different lengths that you find by using this method.
In simple words: Line up the zero mark at one end of the object. Look at where the other end touches the scale. That number is the length.

Exam Tip: Make sure the scale is straight and the object is also straight when you measure - any bend makes the measurement wrong.

Question 16. Estimate the lengths of the following and compare your responses with your friends, in the grade. Write some examples of things that can be lesser than or equal to 1 cm in length. Verify by measuring.
Answer:

Exam Tip: Some objects like ants and grains are very small - you may need a magnifying glass to see the scale markings clearly when measuring them.

Question 17. Take three toy cars and find out how far each one can go. You can use a small wooden ramp or you might like to make a ramp using any material that you have.
Answer:

Exam Tip: Make sure the ramp is at the same angle every time and each car starts from the same spot - this makes it a fair test.

Question 18. Find the longest and the shortest route in this treasure hunt. You can go around the obstacles but cannot jump over them. You can only walk on the yellow tiles and not on the grass. Can you find the length of your route in centimetres? Look for the 1 cm clue in the map.
Answer: Distance of the longest route = 34 cm. Distance of the shortest route = 18 cm.
In simple words: Find the path that covers the most distance on the map and the path that covers the least distance. Use the 1 cm scale shown to measure both routes.

Exam Tip: Count the yellow tiles carefully and use the scale - each tile or set of tiles represents a certain distance when measured on the map.

Question 19. Trace your hand on a piece of paper. Measure it using the scale.
Answer: When I traced my hand and measured it using a scale, I found that my hand is 9 centimetres long according to the picture, and 8 centimetres when I measured it myself.
In simple words: Draw your hand on paper. Then use a ruler to find how many centimetres long your hand is from wrist to fingertip.

Exam Tip: Measure from the bottom of your hand (at the wrist) straight up to the tip of your longest finger to get the true height of your hand.

Question 20. Use your hand to estimate the measurement of any object. Convert into centimetres. Verify using the scale.
Answer:

Exam Tip: Your hand length is a useful personal measuring tool - keep measuring it with your hand to get better at estimating lengths.

Question 21. Ashwin's scale is broken. Can you help him to measure using this scale?
Answer: Blue snowflake fabric = 6 cm (measured from the 8 cm mark to the 14 cm mark on the broken scale). Holly pattern fabric = 4 cm (measured from the 12 cm mark to the 16 cm mark on the broken scale).
In simple words: When a scale does not start at zero, find where one end of the fabric touches the scale, then find where the other end touches. Subtract the first number from the second number to get the length.

Exam Tip: This method works for any broken scale - always subtract the starting mark from the ending mark, even if the scale does not start at zero.

Question 8. Fill in the blanks on the number line below approximately.
Answer: The blanks should be filled as follows: 50 cm (between 40 cm and 60 cm), and 75 cm (between 70 cm and 80 cm). Additionally, the fractional measurements can be positioned as: 1/4 m at 25 cm, 1/2 m at 50 cm, and 3/4 m at 75 cm.
In simple words: Mark the missing numbers on the line by counting up from 0. Each gap of 10 cm helps you find where 50 cm and 75 cm go. The fractions 1/4, 1/2, and 3/4 of a metre match up with these same spots on the ruler.

Exam Tip: Always use the marked intervals as guides - count the spaces between labeled marks to place unlabeled values correctly. Remember that 1 metre = 100 cm, so 1/4 m = 25 cm, 1/2 m = 50 cm, and 3/4 m = 75 cm.

Question 9. The length of a board is 2 metres. Sonu has a decorative border sticker which is 20 cm long. How many such stickers are needed to cover the length of the board completely?
Answer: Convert the board's length to the same unit as the sticker. The board measures 2 metres, which equals 200 cm. Since each sticker is 20 cm long, divide the total length by the sticker length: 200 ÷ 20 = 10. Therefore, 10 stickers are needed to cover the full length of the board.
In simple words: Change 2 metres into 200 cm first. Then divide 200 by 20 to find how many stickers fit along the board. You need 10 stickers.

Exam Tip: Always convert units to match before dividing - if one measurement is in metres and another in centimetres, convert both to the same unit first. This prevents calculation errors.

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Question 1. The Village Sarpanch got the depth of some wells in his village measured by two different people. a) Fill in the blanks such that the depths are the same.
(i) 2 m = 200 cm
(ii) __m = 400 cm
(iii) 6 m = ___cm
(iv) __m = 800 cm
Answer:
(i) 2 m = 200 cm (already filled)
(ii) 4 m = 400 cm
(iii) 6 m = 600 cm
(iv) 8 m = 800 cm
In simple words: To convert metres to centimetres, multiply the metre value by 100. So 4 metres becomes 400 centimetres, 6 metres becomes 600 centimetres, and 8 metres becomes 800 centimetres.

Exam Tip: Remember the conversion rule: 1 m = 100 cm. Multiply the number of metres by 100 to get centimetres. Check your work by converting back - divide the centimetre value by 100 to see if you get the original metre value.

Question 1(b). Identify the wells with the same depth and match them.
Answer: Match the measurements as follows: 1 m 40 cm connects with 140 cm; 4 m 60 cm connects with 460 cm; 2 m 30 cm connects with 230 cm; and 5 m 50 cm connects with 550 cm. Each pair expresses the same depth using different unit combinations or pure centimetre values.
In simple words: First, turn the mixed measurements (like 1 m 40 cm) into just centimetres by multiplying the metres by 100 and adding the extra centimetres. Then find the matching pure centimetre value on the other side.

Exam Tip: Convert mixed measurements (metres and centimetres together) to a single unit before matching. For example, 1 m 40 cm = (1 × 100) + 40 = 140 cm. This makes matching quick and prevents errors.

Let Us Explore

Question. Activity: Students will measure their height using a measuring tape. Make a table in your notebook and complete it.
Answer: A sample completed table is shown with five students' heights measured in both centimetres and metres: Abhishek (122 cm / 1.22 m), Sarika (130 cm / 1.30 m), Babu (135 cm / 1.35 m), Lokesh (118 cm / 1.18 m), and Kavita (136 cm / 1.36 m). Students should measure each classmate's height with a measuring tape and record the measurement in centimetres, then convert to metres by dividing by 100.
In simple words: Measure how tall each student is using a tape measure. Write the height in centimetres. Then change it to metres by dividing by 100 or shifting the decimal point two places to the left.

Exam Tip: Make sure to measure from the top of the head to the floor, keeping the tape straight. Record measurements carefully, and double-check your conversions from centimetres to metres.

Question. Answer the following questions based on the height table above.
Answer:
(1) Height of the tallest child is Kavita (136 cm / 1.36 m).
(2) Height of the shortest child is Lokesh (118 cm / 1.18 m).
(3) Number of children who are more than 1 m tall is 5 (all students in the table exceed 1 metre).
(4) Number of children who are shorter than 1 m is 0 (no student is shorter than 1 metre).
In simple words: Look at each height in the table and compare. Kavita is the tallest at 136 cm. Lokesh is shortest at 118 cm. All five students are taller than 1 metre, and none are shorter.

Exam Tip: When comparing heights, use the same unit throughout - either all centimetres or all metres. Look for the largest number to find the tallest child and the smallest number to find the shortest. Count carefully when asked "how many" fit a particular condition.

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Question 1. Bhola made the boundary of his gardens in the following ways. Circle the boundary that is longest.
Answer: Count the bricks forming each garden's boundary. The first garden has a boundary of 38 bricks. The second garden has a boundary of 40 bricks. The third garden has a boundary of 50 bricks. Since the third garden's boundary uses the most bricks, it is the longest boundary, and it should be circled.
In simple words: Count how many bricks go around each garden's edge. The garden with the most bricks around it has the longest boundary. That's the third garden, which has 50 bricks.

Exam Tip: Perimeter is the distance all the way around a shape. Count every brick or unit that forms the outer edge. The largest count means the longest perimeter.

Question 2. Let us find the perimeter of some shapes using the dot grid. a) Colour the boundary with the longest length in blue. b) Colour the boundary with the shortest length in green. c) Tick the shapes with the same length.
Answer:
(a) The shape with the longest perimeter (among the three shown) is the one on the right, which should be coloured in blue.
(b) The shape with the shortest perimeter is the one in the middle (the octagon), which should be coloured in green.
(c) The rectangle (left) and the cross-shaped figure (right) both have equal perimeters of 20 cm when measured by counting unit segments on the grid. These two shapes should be ticked.
In simple words: Count the number of unit lengths along the edge of each shape. Blue goes on the longest outline. Green goes on the shortest outline. If two shapes have the same total outline length, they get ticks.

Exam Tip: Count every segment around the perimeter - don't skip any edges, even if the shape is irregular or has indents. Shapes that look different can still have the same perimeter if their edges add up to the same total length.

Question 3. Do any of the following shapes have the same perimeter? Tick them.
Answer: Shapes A, C, and F all have a perimeter of 10 cm. These three shapes should be ticked. Shapes B, D, and E have different perimeters (14 cm, 14 cm, and 14 cm respectively), so B, D, and E should also be ticked since they share the same 14 cm perimeter with each other.
In simple words: Measure around each shape by counting the unit lengths that form its outline. If two or more shapes have the same total outline length, they have the same perimeter - mark those shapes.

Exam Tip: Perimeter is the total distance around a closed shape. Shapes with straight edges are easier to measure - count each unit segment. Mark all shapes that share the same perimeter value, not just pairs.

Question 4. Tick the garden with the minimum perimeter.
Answer: Among the three garden shapes shown, the first garden (a rectangle) has a perimeter of 12 cm. The second garden (an irregular L-shaped figure) has a perimeter of 10 cm. The third garden (also L-shaped) has a perimeter of 12 cm. The second garden has the smallest perimeter of 10 cm, so it should be ticked.
In simple words: Count the bricks or unit lengths around each garden's edge. The garden with the fewest total units going around it has the minimum perimeter. That one gets a tick.

Exam Tip: The minimum perimeter is the smallest total distance around any shape. Count carefully, paying special attention to indented or irregular shapes - every inward corner adds extra length to the perimeter.

Question 5. Estimate and measure the perimeters of shapes around you using a scale and write them in the space given below.
Answer: A sample data table shows measured perimeters: Desk (300 cm estimated and actual), Blackboard (600 cm estimated, 624 cm actual), Classroom floor (2600 cm estimated, 2750 cm actual), Door (450 cm estimated, 462 cm actual), Window (340 cm estimated, 358 cm actual), and Notebook (80 cm estimated, 86 cm actual). Students should measure the outline of classroom objects with a measuring scale, estimate the perimeter first by rough calculation, then measure precisely and record both values.
In simple words: Pick an object in your classroom. First, guess how far it is all the way around - that's your estimate. Then use a measuring scale to find the actual distance. Write both numbers in your table.

Exam Tip: Estimates help develop number sense - they don't need to be perfect, but should be close to the actual measurement. Measure along the actual edges of the object for accuracy, and add up all sides for the perimeter.

Question 6. Draw three different shapes with perimeter of 20 cm.
Answer: Three different shapes can be drawn on a dot grid, each with a perimeter of 20 cm: (1) A rectangle with dimensions 5 cm × 5 cm (perimeter = 5 + 5 + 5 + 5 = 20 cm); (2) A rectangle with dimensions 6 cm × 4 cm (perimeter = 6 + 4 + 6 + 4 = 20 cm); and (3) An irregular shape such as a modified L-shape or other polygon that uses 20 unit lengths around its boundary. Students should draw each shape on the dot grid and verify the perimeter by counting unit segments or calculating using the dimensions.
In simple words: Draw three different shapes on the dot grid. Count the units going around each shape. Make sure all three have a total outline of exactly 20 cm. They can be different shapes - rectangle, L-shape, or something else - as long as the perimeter matches.

Exam Tip: Multiple shapes can have the same perimeter - focus on counting the boundary units accurately. Draw your shapes lightly first, count the perimeter, and adjust if needed before finalizing. Rectangles are easiest to calculate: P = 2 × (length + width).