- Right angle
Any angle which measures exactly 90^0 is said to be a right angle. The idea can be
taught by using the paper folding. Take a sheet of paper and fold it to make two
halves. Now fold it once again to halve the paper on the other way. The two creases
formed will make an angle of 90o between them.
The edges of a Braille slate or Braille paper normally make an angle of 90o.^ The child
needs to be given hands on experience through the objects which he/she is familiar
with.
- Zero angle
If the initial side and terminal side coincide, then the angle formed is said to be a
zero angle.
The idea of zero angle is totally abstract in nature. Place a sheet over the other and
ask the child whether or not any angle is formed. Such a condition be explained as
Zero angle.
- Acute angle
Any angle which measures greater than zero degree and less than 90o is called an
acute angle. Explain the concept clearly and then enable the child to make an acute
angle on a sheet of paper by folding it accordingly. Since the child himself is performing
the activity he/she will be able to understand the idea clearly.
- Obtuse angle
Any angle whose measure is greater than 90^0 and less than 180^0 is called an obtuse
angle.
AB
C
O
90 O
A
O θ B
