In Progress
Lesson 9, Topic 1
In Progress

# Angles in a Triangle

Lesson Progress
0% Complete

### Triangle

Tri-angle means three angles.

A triangle is the simplest form of polygon with three sides and three interior angles.

Sum of angles in a triangle is 180º

$$\scriptsize \angle A \: + \: \angle B \: + \: \angle C = 180^o$$

From the above diagram above

a = y (alternate angles

b = z (alternate angles

but, a + x + b = 180º (sum of angles on a straight line).

Since a + b = y + z

Hence x + y + z = a + x + b = 180º

Therefore, the sum of angles of a triangle = 180º

error: