Answer: B. 5root(3)
Use Pythagorean’s theorem to solve this problem. We know one side and the hypotenuse, so we can solve for the other side.
a² + b²= c²
5² + b² = 10² (plug in 5 for one side, and 10 for the hypotenuse)
25 + b² = 100 (square 5 and 25)
b² = 75 (subtract 75 from both sides)
b=√(75) (take the square root of both sides)
b=√(25*3) (factor out a square)
b=5√(3) (simplify radical)
