The vertex angle of an isosceles triangle is 20° less than the sum of the base angles. Which system of equations can be used to find the measure of the vertex and base angles?
Accepted Solution
A:
The base angles are equal and we'll call those "x" and "x". We'll call the vertex angle y. A) y + 2x = 180 B) y + 20 = 2x we can algebraically shift "B)" into B) y - 2x = -20 then we'll add that to "A)" A) y + 2x = 180 2y = 160 "y" the vertex angle = 80 degrees each base angle = 50 degrees