B.) 2

C.) 3

D.) 2√5

E.) 4

**{sum of the squares of the legs, a and b, is equal to the square of the hypotenuse}**

a² + b² = c²

__Pythagorean Theorem__a² + b² = c²

4² + b² = 5² {substituted legs and hypotenuse into Pythagorean Theorem}

16 + b² = 25 {evaluated exponents}

b² = 9 {subtracted 16 from each side}

b = 3 {took positive square root of each side}

**C.) 3**

**Ask Algebra House**