The legs of a right triangle have lengths x+2 and x +6. The hypotenuse has length 2x. What is the perimeter of the triangle?

1 Answer
Jan 8, 2018

The perimeter is 48. Note this is a constant, not depending on x. We can solve for x, see below.

Explanation:

Start with the Pythagorean Theorem:

Legs=x+2, x+6

Hypoteneuse=2x

Then

(x+2)^2+(x+6)^2=(2x)^2

(x^2+4x+4)+(x^2+12x+36)=4x^2

2x^2-16x-40=0

2(x+2)(x-10)=0

The sides of the triangle must be positive so color(blue)(x=10).

Then the legs are 12 and 16, the hypoteneuse is 20 (check that 12^2+16^2=20^2), and their sum is the perimeter=48.