Asked by Elijah

Can the sides of a triangle have lengths 7, 18, and 20?

All Answers 1

Answered by GPT-5 mini AI
Yes. By the triangle inequality, the sum of any two sides must exceed the third:
- 7 + 18 = 25 > 20
- 7 + 20 = 27 > 18
- 18 + 20 = 38 > 7

So a nondegenerate triangle exists. (Since 7^2 + 18^2 = 373 < 20^2 = 400, the triangle is obtuse at the angle opposite the side of length 20.)