Tip
You will need to know how to find the hypotenuse or the side lengths of a right triangle using the Pythagorean Theorem.
Pythagorean Theorem: (a2 + b2 = c2)
Sample Problem
In the figure, AB = 3, AD = 4, and CD = 5. What is the length of BC?
Answer Options
(A) 5
(B) 10
(C) 25
(D) 5√2
(E) 10√2
View Correct Answer
(D) 5√2
In the right triangle ABD, the two legs equal 3 and 4. So, by the Pythagorean theorem, 32 + 42 = BD2 or BD = 5. In the right triangle DBC, the two legs are both equal to 5. By the Pythagorean theorem, 52 + 52 = BC2 , so BC = √50 = 5√2.
