Question

What is the sum of the interior angles of a triangle?

Answer 1

Sum of angles in any triangle is `180^o`

Explanation:

Both angles `alpha` are Alternate Interior Angles and, therefore, are congruent (equal in value).
Both angles `gamma` are Alternate Interior Angles and, therefore, are congruent (equal in value).

The sum of all three angles `alpha`, `beta` and `gamma` inside a triangle equals to sum of angles `alpha`, `beta` and `gamma` at the top of a picture that together form straight angle of `180^o`.