Eight-sided polygon has integer side lengths. It can be divided into a rectangle and a square, as shown.
The area of the square is greater than the area of the rectangle. The product of the two areas is equal to 98. Which of the following could be the perimeter of ?
, 2023
Pick one
Solution
Since is a square and its side lengths are integers, then its area is equal to a perfect square. Since the product of the areas of and (the rectangle) is equal to 98, then the area of is a divisor of 98. The positive divisors of 98 are 1, 2, 7, 14, 49, and 98. There are exactly two divisors of 98 that are perfect squares, namely 1 and 49. Since the area of is greater than the area of , then the area of is 49, and so the area of is 2 (since ). Square has area 49, and so . [[IMAGE0]] The perimeter of is equal to Since the side lengths are integers and the area of is 2, then either (and ), or (and ). If , then the perimeter of is . Since 30 is not given as a possible answer, then and the perimeter is .

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