The solution is D.
From the top right & left corners drop a perpendicular line to the base forming right triangles on the right and left sides. This makes the center [art of the base 12 and the base of the triangles 7. Use the Pythagorean Theorem to find the altitude, which is the same as the height.
7^2 + b^2 = 25^2
b^2 = 25^2 - 7^2
b = 24
