The two pyramids are cross-cut parallel to their bases at one-third of the height. What the ratio of the areas of these cross-sections ?

David must install fencing around a lot that is shaped like a right angle.the side of lot that runs east-west is 200 ft long.the side of the lot runs north-south is 125 ft long.calculate how many feet of fencing he will need to surround the entire lot.

Having a hard time understanding this question (see attachment).

Rationalize the denominator- 12x/√x-10