CBSE Class 4 Maths Geometry HOTs

HOTS

1. Draw figures to show the following:
a. Point M lies on line segment P̅Q̅  

Answer: 

2. Raj and Sheila ran a race on a straight track. They reached the end at the same time, which means they ran with exactly the same speed.
Then they ran with the same speed on a circular track. (See the picture)
But this time Raj won the race. Why?
(Hint: Think! Is the distance they ran the same now?) 

Answer:  Distance ran by Raj is less as compared to Sheila as radius of the circular track covered by Raj is less than the radius of the track covered by Sheila.

3. If AB=5 cm and CD=2 cm, construct a segment whose length is equal to 2AB+3CD. 
Answer: 2AB + 3CD = 2×5+3×2=10+6=16 cm

SUMMARY

1. A point is represented by a dot on a plane paper.

2. A line is a set of points extending in both the directions endlessly.

3. A line has no end point and no definite length.

4. A line segment has two end points and a definite length.

5. A ray has one end point and no definite length.

6. A circle is a simple closed curve whose each point is equidistant from a fixed point in it. This fixed point is called centre of the circle.

7. 

8. The distance between the centre of a circle and a point on the circumference is called its radius.

9. A line segment which contains the centre of the circle and whose end-points lie on the circumference of a circle is called diameter of the circle.

10. Diameter of a circle = 2 × radius of the circle.

11. Half of a circle is called a semi-circle.

12. A line segment whose end-points lie on the circumference of a circle is called a chord.

13. Diameter of a circle is the greatest chord.

14. A part of the boundary of a circle is called an arc.

15. The measure of the closed curve forming a circle is called its circumference.

ERROR ANALYSIS

1. Students don’t put arrow on both sides of the line.

2. While drawing the line segment, students start from point 1 on the scale rather than starting from point 0.

3. Enough practice to draw circle using compasses should be given.

4. Sometimes students use a broken scale.

ACTIVITY

To find the centre of a circle by paper folding

This activity is based on the fact that the diameter of a circle passes through the centre of the circle and so, two diameters of a circle will meet each other at the centre.
Place a circular object such as a big bangle, a ring, lid of a jar etc. on paper sheet and trace its outline to form a circle. Cut out the circle. 

Fold the circle in half and press the fold tight to form a crease.
Again, fold the paper in half.
Open up the folded paper.
Two creases are seen on the paper – one horizontal and one vertical – both meeting at a point in the middle. Each crease is a diameter of the circle and their meeting point is the centre of the circle. Darken the diameters with a coloured pen and label the centre as O.

Project
After learning to draw a circle with a compass, students can make beautiful designs, can colour and paste in a scrap book. Some of the common designs are:

Try some more designs.
Students can make this caterpillar using circles. Draw circles using a coin or a bangle.
Colour it.