Find an integer, x, such that 2, 4, and x represent the lengths of the sides of an obtuse triangle.

A^2 + b^2 < c^2 for the triangle to be obtuse

2^2 + 4^2 < x^2

4 + 16 < x^2

20 < x^2

sqrt 20 = 4.7 approx 5

x needs to be greater than or equal to 5 for the triangle to be obtuse.

4 + 16 < 25

20 < 25