Arectangular lot whose perimeter is 290 ft290 ft is fenced along three sides. an expensive fencing along the lot's length cost $ 36$36 per foot. an inexpensive fencing along the two side widths costs only $ 6$6 per foot. the total cost of the fencing along the three sides comes to $ 4260$4260. what are the lot's dimensions

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?