Question

I am struggling with triangles missing angles with the formula if you could explain your answer step by step that would be great. What is the formula for the isosceles triangle?

Answer 1

See below.

Explanation:

The 3 angles of all triangles add up to 180 degrees.

An isosceles triangle has 2 of its angles equal.

So if one of the angles is 130 degrees then there cant be another one of 130 degrees as that would make 260 degrees.

So the other 2 angles are equal and their measure is (180 - 130) / 2

= 50 / 2

= 25 degrees.

The 2 equal angles are both 25 degrees.