- Equiangular triangles
When the corresponding angles of two triangles are exactly the same they are said to
be equiangular triangles. Note that the equiangular triangles are similar triangles.
The idea may be explained orally in addition to the provision of two equiangular
triangles constructed either by paper or plastic.
- The sum of the angles of a triangle is 180o
In any triangle, the sum of the measures of the angles of the triangle will always be
equal to 180o or a straight angle.
The procedure mentioned in the creative mathematics section may be followed to
enable the child to understand the idea by performing the activity.
- In any triangle, the sum of the measures of any two sides is always greater than
the third side
The idea can be demonstrated using paper folding or tactile material.
Explain the idea orally to the child. Now cut a triangle into three pieces so that the
sides are intact.
Select any two sides, place them together and measure the length of the combined
sides. Now measure the third side. Allow the child to explore the lengths of both and
let the child measure them. On measuring the sides, the child will be able to understand
that the sum of the measures of any two sides of a triangle is always greater than the
third side.
A + B + C = 180 o
C B
A
Cut here
