A small, rectangular park has a perimeter of 560 feet and a diagonal measurement of 300 feet. What is its area, in square feet? Pick one:
A) 43,200	B) 19,600	C) 20,000	D) 20,400	E) 20,800

Rationale: "you can avoid a lot of work in this problem by recognizing that , with the info provided , the diagonal forms a triangle inside the rectangle with sides that have a 3 : 4 : 5 ratio . diagonal = 200 2 x + 2 y = 560 , or x + y = 280 a ^ 2 + b ^ 2 = c ^ 2 for each the sides of the triangle using the ratio 3 : 4 : 5 for sides , and knowing c = 300 , you can deduce the following a = 180 b = 240 180 x 240 = 43,200 a is the answer ."
Answer: A