The procedure followed in teaching the idea of acute angle may be followed to enable
the child to understand the idea of obtuse angle also.
- Straight angle
An angle which measures exactly 180^0 is called a straight angle. The idea needs to be
explained orally, in addition to the provision of a sheet of paper in which the sides
always form a straight angle.
- Reflex angle
Angles which measure greater than 180^0 and less than 360^0 are called as reflex angles.
The idea may explained to the child through a tactile diagram.
- Angle at a point
An angle which measures exactly 360^0 is called the angle at a point.
To enhance the understanding level of the child, provide him/her with four equal
pieces of paper which are torn from a sheet, by folding it both vertically and horizontally.
Facilitate the child to understand that any corner of the four pieces form a right
A
B
A^180 B
0
AB
C
D
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