# A right triangle has one leg twice as long as the other. Find a function that models its perimeter P in terms of the length x of the shorter leg.

A right triangle has one leg twice as long as the other. Find a function that models its perimeter P in terms of the length x of the shorter leg.

I have tried adding 2x + x for the two legs, however there is also a hypotenuse, but there are no lengths given for any of the sides.

The function must be described as P(x).

• You're off to a good start. Use the Pythagorean Theorem to find the hypotenuse in terms of $x$. – paw88789 Sep 15 '14 at 3:10

Use the Pythagorean theorem to find the third side. It states that sum of squares of the sides which are at right angle is equal to the square of hypotenuse i.e., the third side. So the third side is $\sqrt{x^2+{(2x)}^2}$.
Shorter cathetus: $x$. Longer cathetus: $2x$. Hypotenuse: $\sqrt{x^2 + (2x)^2}$. Do the simple algebra and just add 'em up.