Question

What is the greatest possible whole-number value of the congruent side lengths?

9 cm
10 cm
14 cm
15 cm

Answer 1

In an obtuse triangle, the square of the longest side is greater than the sum of squares of the other two sides. So the equal legs must have a length

L^2 + l^2=2l^2

14^2+14^2=20^

196+196=400

392=400

14cm is the greatest