Page 169 - Start Up Mathematics_4

INDIVIDUAL ACTIVITY

To understand different types of angles using paper folding techniques
Things We Need: Coloured paper or white sheets of paper and a pencil

How To Do:
A. Straight angle

1. Take a sheet of paper and fold it into two halves.
180°
2. Unfold it and mark a point O on the crease formed. O

3. The angle formed at O is a straight angle.

B. Right angle
1. Take a sheet of paper and fold it into two halves.

2. Again fold the folded paper into two halves.
3. Unfold the paper. Four equal angles are formed by
two intersecting creases.
4. Each angle is a right angle.

C. Acute angle
1. Take a sheet of paper and fold it into two halves.
2. Again fold the folded paper as shown.

3. Unfold the paper. Four angles are formed by creases. A
4. ∠AOB is an acute angle. O B

D. Obtuse angle

1. Take a sheet of paper and fold it into two halves.
2. Again fold the folded paper as shown.
3. Unfold the paper.

4. ∠PQR is an obtuse angle. P
R
Q

161