The angle calculate of the base angles of an isosceles triangle are shown by x and the vertex angle is 3x + 10. Determine the measure of a base angle.

a. 112°

b. 42.5°

c. 34°

d. 16°

c. The addition of the measures of the angles of a triangle is 180. The question is asking us to solve for x. The equation is x + x + 3x + 10 = 180. Simplifying the equation, 5x + 10 = 180. Subtract 10 from each side; 5x = 170. Divide each side by 5; x = 34. If you select a, you solved for the vertex angle. If you select b, you wrote the original equation incorrectly as x + 3x + 10 = 180. If you select d, you wrote the original equation incorrectly as x + x + 3x + 10 = 90.