Question

Two sides of a triangle measure 5 inches and 9 inches. Which of the following is a measure of a possible 3rd side of the triangle?

A. 2 inches
B. 5 inches
C.15 inches
D.18 inches

Answer 1

B. 5 inches

Explanation:

This is because of the triangle inequality theorem which states "The sum of the lengths of any two sides of a triangle is greater than the length of the third side." So, since 5+9 is 14 it has to be less than 14. Also, because 5+2 is 7 and that is not greater than 9 it has to be 5 inches.