Answer
$\sqrt {130}=x$
Work Step by Step
The Pythagorean Theorem states that if $a$ and $b$ are the legs of a right triangle and $c$ is the hypotenuse, then $a^2+b^2=c^2$. We plug in the values for $a$, $b$, and $c$, using the legs and the hypotenuse of the right triangle shown, and then solve the equation using the properties of algebra and equality: $$7^2+9^2=x^2$$$$49+81=x^2$$$$130=x^2$$$$\sqrt {130}=\sqrt {x^2}$$$$\sqrt {130}=x$$
