Question

Two lengths of a triangle are shown.

Triangle A B C. Side A B has a length of 6 feet and side A C has a length of 6 feet.
Which could be the length of Side B C?
11 ft
13 ft
15 ft
18 ft

Answer 1

By the triangle inequality, the third side must be less than 6 + 6 = 12 and greater than |6 − 6| = 0. So BC must be between 0 and 12 (not including 12). Among the choices only 11 ft satisfies this.