Question

The degree measure of the interior angles of a triangle is in the ratio of 2:5:5. What is the degree measure of the smallest angle?
(A) 20

(B) 30

(C) 40

(D) 60

(E) 80

Answer 1

The three angles are 2x, 5x, and 5x for some positive real number x.

The inside angles always add to 180 degrees for any triangle.

2x+5x+5x = 180

12x = 180

x = 180/12

x = 15

That leads to the following angles:

• 2x = 2*15 = 30
• 5x = 5*15 = 75
• 5x = 5*15 = 75

The three angles of the triangle are 30, 75, 75

Answer: 30