Question

Which of the following could be the third side of an obtuse triangle with the other two side lengths of 6 and 7.

5
8
9
10

Answer 1

Pythagorean theorem.
a^2+b^2=c^2
6^2+7^2=c^2
36 + 49 = c^2
85 = c^2
sqrt of 85 = 9.22

So the best answer would be C. 9