Question

Which set of side lengths can be used to construct a triangle?

A. 1, 2, 3
B. 6, 9, 15
C. 7, 12, 20
D. 9, 12, 17

Answer 1

We verify: a < b + c; b < a + c; c < a + b;

Only a = 9, b = 12, c = 7 verify the conditions: 9 < 19; 12 < 16; 7 < 21;

The correct answer is D.

Explanation: