Question

The third angle of a triangle is the same size as the first. The second angle is 4 times the third. Find the measure of angles.

Answer 1

1st angle 30°

2nd angle 120°

3rd angle 30°

Explanation:

Let's call

A = 1st angle

B = 2nd angle

C = 3rd angle

In every triangle it holds

A + B + C = 180°

Now, if the third angle of the triangle is the same size as the first

A = C

If the second angle is 4 times the third

B = 4C

we have then

C + 4C + C = 180° ===> 6C = 180° ===> C = 30°

If C = 30° then A = 30° and B = 120°