Question

Find x when there's a right triangle,

Answer 1

 x^2 = 2^2 + 3^2
 x^2 = 4 + 9 = 13
 so
 hypotenuse = x = √13

hope that helps

Answer 2

To find out the missing leg of a right triangle, you have to use the Pythagorean Theorem which is a^2 + b^2 = c^2. C is the hypotenuse. So, substitute the numbers into that equation. 

2^2 + 4^2 = x
4 + 16 = x
20 = $\sqrt{x}$