Distributive property with no known numbers

Question

The second angle of a triangle is four times as large as the first angle. The third angle is 30º greater than the first angle. How large are the three angles?

Answer 1

f = first angle

4f = second angle

f + 30 = third angle

 

180° is the sum of the angles of a triangle.

180° = f + 4f + f + 30

180 = 6f + 30

150 = 6f

25 = f

 

The three angles are 25°, 100°, and 55°.