Samacheer Kalvi Class 5 Maths Solutions Term 1 Chapter 1 Geometry InText Questions

Activity (Text Book Page No. 4)

I. Write the 3-D shapes lying around us

II. What will you observe, if you look at this object from the front?

 

Question 1.
Answer:

🎯 Exam Tip: When viewing 3D objects from the front, focus on the visible face and ignore the depth or sides.

 

Question 2.
Answer:

🎯 Exam Tip: Imagine yourself directly in front of the object and draw only what you can see, ignoring hidden parts.

III. What will you observe, if you look at this object from the sideways?

 

Question 1.
Answer:

🎯 Exam Tip: Different viewing angles of a 3D object will show different 2D shapes, highlighting specific faces.

 

Question 2.
Answer:

🎯 Exam Tip: For stacked objects, the side view will show the height and width of the exposed surfaces from that angle.

Practice (Text Book Page No. 8)

Look at the following shapes. Draw that how will it be changed after 1/3 and 1/6 of a turn?

Answer:

🎯 Exam Tip: To predict rotation, imagine turning the shape around its center point by the specified fraction of a full circle.

Activity (Text Book Page No. 9)

While standing in front of a mirror, see your image.

Observe your image in the mirror when moving back and coming front to the mirror again, what do you infer?

 

Question 1. Your image in the mirror is (bigger, smaller, same size)
Answer: same size
In simple words: When you look in a flat mirror, your reflection will be the same size as you are. It does not get bigger or smaller.

🎯 Exam Tip: Understand that plane mirrors create virtual images that are the same size as the object and are laterally inverted.

 

Question 2. When you go back, your image is moving (backward, forward)
Answer: backward
In simple words: If you step back from a mirror, your reflection will also seem to move back, keeping the same distance. This is because the image forms behind the mirror at an equal distance from it.

🎯 Exam Tip: The image in a plane mirror moves with the same speed as the object but in the opposite direction relative to the mirror.

 

Question 3. The distance between you and mirror and the distance between you and your image is (equal, unequal)
Answer: equal
In simple words: The distance from you to the mirror is always the same as the distance from the mirror to your image. This means your reflection appears to be as far behind the mirror as you are in front of it.

🎯 Exam Tip: A key characteristic of plane mirror images is that the object distance equals the image distance.

 

Question 4. When you come forward to the mirror, your image is moving (forward, backward)
Answer: forward
In simple words: If you walk towards the mirror, your reflection will also appear to walk towards you.

🎯 Exam Tip: The image always moves in sync with the object, maintaining the distance rule relative to the mirror.

 

Question 5. When you raise your right hand, the image in the mirror looks like, hand is raising. (right, left)
Answer: left
In simple words: When you lift your right hand, your reflection appears to lift its left hand. This is called lateral inversion.

🎯 Exam Tip: Remember lateral inversion: left and right are swapped in a plane mirror image, but top and bottom remain the same.

 

Question 6. When you raise your left hand, the image in the mirror looks like, hand is raising. (right, left)
Answer: right
In simple words: If you lift your left hand, your reflection will show its right hand going up. The image is a mirror opposite.

🎯 Exam Tip: Lateral inversion is a fundamental property of images formed by plane mirrors.

 

Question 7. Look at this shape:

Which image shows a reflection? ✓ the answer given below

Answer: B
In simple words: A reflection is like looking in a mirror. The shape flips over but does not turn. Image B shows the shape flipped horizontally, just like a reflection.

🎯 Exam Tip: A reflection creates a mirror image, flipping the object across an axis without rotation.

Try yourself (Text Book Page No. 10)

Draw some of your favourite shapes and draw its reflection images on a chart and show it to your teacher.

Project (Text Book Page No. 12)

 

Question 1. List out 2 symmetrical objects that you know
Answer:

🎯 Exam Tip: Symmetry means that a shape can be folded or cut in half so that both sides match perfectly. Look for objects that are the same on both sides of a line or point.

 

Question 2. Tick among the following picture, having symmetry

Answer: House, Crab, and Whale are symmetrical. The octopus is not.
In simple words: You need to find pictures that can be split into two identical mirror halves. The house, crab, and whale can be split in half symmetrically.

🎯 Exam Tip: A shape has symmetry if it can be divided by a line (axis of symmetry) into two parts that are mirror images of each other.

 

Question 3. Complete the other half to make the given figure as symmetrical.

 

Question 3. Question 1.
Answer:

🎯 Exam Tip: To complete a symmetrical figure, draw the mirror image of the given half across the line of symmetry.

 

Question 3. Question 2.
Answer:

🎯 Exam Tip: Pay close attention to each segment and angle when reflecting complex shapes to ensure perfect symmetry.

 

Question 4. Draw the lines of symmetry for the following figures then count and write the number of lines.

Answer:

🎯 Exam Tip: Lines of symmetry can be horizontal, vertical, or diagonal. Rotate the shape mentally to find all possible lines of division.

Think it (Text Book Page No. 13)

 

Question 1. Can we divide the irregular solids symmetrically? if no why?
Answer: No, we cannot divide irregular solids symmetrically because their parts would not be equal or mirror images of each other. Irregular shapes lack the consistent form needed for perfect symmetry.
In simple words: No, you cannot cut irregular shapes perfectly in half so both sides match. They don't have the same shape on both sides.

🎯 Exam Tip: True symmetry requires precise matching of parts when folded or divided, which is absent in irregular shapes.

 

Question 2. Write the English alphabets that can't be divided symmetrically?
Answer: The English alphabets that cannot be divided symmetrically are F, G, L, N, P, Q, R, S. These letters do not have any line of symmetry, meaning you cannot fold them in half to get two matching sides.
In simple words: Letters like F, G, L, N, P, Q, R, S cannot be split perfectly in half, either sideways or up and down.

🎯 Exam Tip: Mentally draw a vertical and horizontal line through each letter to test for symmetry; if no line works, it's asymmetrical.

 

Question 3. Write the English alphabets which are divided symmetrically?
Answer:

🎯 Exam Tip: Capital letters often have clear lines of symmetry, either vertical (like A, M, T), horizontal (like B, C, D), or both (like H, I, O, X).

 

Question 4. Circle has many lines of symmetry. Is it true? why?
Answer: Yes, it is true that a circle has an infinite number of lines of symmetry. This is because any line that passes through the center of the circle and acts as a diameter will divide the circle into two identical halves, making it symmetrical along all its diameters.
In simple words: Yes, a circle has endless lines of symmetry. You can cut a circle through its middle point in any direction, and it will always make two matching halves.

🎯 Exam Tip: Remember that any diameter of a circle is a line of symmetry, and a circle has infinitely many diameters.

 

Question 5. Find the three numbers between 1 and 9 that can be divided symmetrically?
Answer: The three numbers between 1 and 9 that have symmetry are 1, 3, and 8. These numbers can be divided by a line (horizontal or vertical) to create two mirror-image halves.
In simple words: Out of the numbers 1 to 9, only 1, 3, and 8 can be folded perfectly in half so both sides match.

🎯 Exam Tip: Visualize each numeral and consider both horizontal and vertical lines of symmetry to identify which ones are symmetrical.

 

Question 6. Find two numbers between 1 to 9 having two lines of symmetry?
Answer: The only number between 1 and 9 that has two lines of symmetry is 8. It has both a vertical and a horizontal line of symmetry. Numbers like 1 and 3 only have one line of symmetry, while others like 2, 4, 5, 6, 7, and 9 have no lines of symmetry.
In simple words: Only the number 8, between 1 and 9, can be folded both up-down and side-to-side to make perfect halves. So, it has two lines of symmetry.

🎯 Exam Tip: Carefully test each number (1-9) for vertical and horizontal symmetry to confirm how many lines each possesses.

Try These (Text Book Page No. 14)

 

Find out which of these can be made into a box by folding along the dotted lines. Put a tick mark for the correct option.
Answer: The first net shown can be folded along its dotted lines to form a box. To test this, you can imagine folding each part, ensuring that all sides connect without gaps or overlaps. This type of shape is also known as a 'net' of a 3D solid, which shows all its faces laid out flat.
In simple words: Only the first shape can be folded up to make a closed box. Imagine folding each part to see if it fits together perfectly to make a 3D shape.

🎯 Exam Tip: For nets, count the number of faces and ensure they correspond to the desired 3D shape (e.g., 6 faces for a cuboid). Visualize the folds carefully.

Activity (Text Book Page No. 16)

 

Match the net with the shape you will get by folding.
Answer:

🎯 Exam Tip: Practice visualizing how flat nets fold into 3D shapes, paying attention to how edges meet and form corners.

Introduction of Angles (Text Book Page No. 18)

To get the feel of an angle through observation of objects and by paper folding:

Answer:

🎯 Exam Tip: Clearly identify the vertex (the point where the arms meet) and the two arms that form the angle for precise naming.

 

Question. Name the types of angles formed in the following items.
Answer:
(i) The first item (a corner or square shape) forms a Right angle.
(ii) The second item (scissors opening slightly) forms an Acute angle.
(iii) The third item (pliers opening wide) forms an Obtuse angle.
This helps us quickly identify different types of angles just by looking at them.
In simple words: Look at each picture and say what kind of angle it shows. A square corner is a right angle, a small opening is an acute angle, and a wide opening is an obtuse angle.

🎯 Exam Tip: Visualizing real-world objects can help you identify angles more easily; think of a book corner for a right angle.

Try These (Text Book Page No. 20)

 

Question. Identify and classify the types of angles shown in the following figures.
Answer:
(i) The first shape (a parallelogram) shows an Obtuse angle.
(ii) The second shape (a rhombus) shows an Acute angle.
(iii) The third shape (a hexagon-like figure) shows an Obtuse angle.
(iv) The fourth shape (a square) shows a Right angle.
Recognizing angles in different shapes helps us understand their properties better.
In simple words: Look at each shape and decide what kind of angle is there. An obtuse angle is wide, an acute angle is narrow, and a right angle is like a perfect corner.

🎯 Exam Tip: Remember that geometric shapes often contain multiple types of angles; practice identifying them within different figures.

Do Yourself (Text Book Page No. 21)

 

Question. Draw 5 objects with a right angle.
Answer: Many common objects around us have right angles. Examples include the corners of a table, a book, a door, a window, or a picture frame. A right angle always forms a perfect 'L' shape or a square corner. These objects help us see right angles in daily life.
In simple words: Think of things with square corners, like a book, a table, or a window. Those corners are right angles.

🎯 Exam Tip: Use a square object, like the edge of your notebook, to check if an angle is truly a right angle (90 degrees).

Try These (Text Book Page No. 21)

 

Question 1. Classify the following angles (acute angle, obtuse angle and right angle): 30°, 45°, 60°, 90°, 120°, 130°, 170°, 75°.
Answer:

These classifications help us understand the size of different angles compared to a right angle.
In simple words: Acute angles are smaller than 90 degrees. A right angle is exactly 90 degrees. Obtuse angles are bigger than 90 degrees but less than 180 degrees.

🎯 Exam Tip: Remember the key degree for classification is 90° (right angle). Angles less than 90° are acute, and those greater than 90° (up to 180°) are obtuse.

 

Question 2. Observe the following pictures and write the name of the angles in their box.
Answer:

It's important to be able to visually identify different types of angles quickly.
In simple words: Look at each picture and decide if the angle is small (acute), a perfect corner (right), or wide (obtuse).

🎯 Exam Tip: Practice drawing angles of different types to improve your visual recognition and understanding without needing a protractor every time.

Activity (Text Book Page No. 22)

 

Question. Draw a right angle, an acute angle and an obtuse angle by tracing.
Answer: To draw these angles by tracing, you can use a grid or ruler. A right angle looks like the corner of a square. An acute angle is smaller, like a slice of pizza. An obtuse angle is wider, like a mouth opening wide. Tracing helps you get a feel for how big each angle is. The example image shows various angles drawn on a grid, helping visualize their forms.
In simple words: You can draw a right angle (like a perfect corner), an acute angle (smaller than a corner), and an obtuse angle (wider than a corner). Tracing helps you practice making them correctly.

🎯 Exam Tip: When drawing angles, aim for neatness and ensure the vertex (point) is clearly defined for each angle.