The answer is d. If you are solving for a missing leg of a triangle you want to use Pythagoras Theorm. a² + b² = c² a and b will be the legs you have been given and c is your hypotenuse (x). 5² + 5² = c² 25 + 25 = c² 50 = c² since you are solving for c not c² you must take the √ of 50 √50 does not come out as an even number so you must try to think of two numbers that you can multiply and get 50 one should be a perfect square. In this case it is 25 and 2 √25 = 5 √2 does not come out even so we express our answer as 5√2
