Question

The perimeter of an equilateral triangle is 15 inches more than the perimeter of a square, and the side of the triangle is 7 inches longer than the side of the square. What is the side of the triangle?

Answer 1

13 inches

Explanation:

in an equilateral triangle all sides had we the same length.

so, the perimeter is simply 3×one triangle side.

and the perimeter of the square is 4×one square side.

x = triangle side length

y = square side length

3x = 4y + 15

x = y + 7

we use the second equation as substitution in the first equation.

3(y + 7) = 4y + 15

3y +21 = 4y + 15

6 = y

x = y + 7 = 6 + 7 = 13 inches