The answer is 120.75, I believe answer d is a typo and should be 120.75. How you find this is by comparing the ratio's of the two triangles. They share two angles in common, the vertical angles where they meet and the right angle, this means the third angles are also equal. With this, we know the triangles are similar, and thus their sides share a common ratio. We can then compare the 64 ft side to the 92 ft side, and also the 84 ft side with the x, we make the equation 64/92 = 84/x and solve for x using cross multiplication. Giving us 84*92 = 64*x, or (84*92)/64 = x, 7728/64 = x, and finally 120.75 = x. I hope this helps. I would be happy to set up a lesson and help more online. Thanks.