Question

17) The measures of two sides of a triangle are (2x + 3y) and (5x – 2y). If the perimeter

of the triangle is (12x + 5y), what is the measure of the third side?

Answer 1

5x +4y

Explanation:

The perimeter of a triangle is the sum of side lengths. That fact can be used to find z, the length of the third side.

(2x +3y) +(5x -2y) +z = 12x +5y . . . . sum of sides is perimeter

z = (12x +5y) -(7x +y) . . . . . . . . . . . . subtract (7x+y) from both sides

z = 5x +4y . . . . . . . . . collect terms; the length of the third side

The third side of the triangle is (5x +4y).