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advanced-mathA rectangle has a perimeter of 36 cm. What dimensions maximize the area?
A
9 cm by 9 cm
B
10 cm by 8 cm
C
12 cm by 6 cm
D
18 cm by 18 cm
Correct Answer: A
Choice A is the correct answer. For a fixed perimeter, a rectangle's area is maximized when it is a square.
- Perimeter .
- Side .
- Dimensions: 9 cm by 9 cm. Area = 81.
Choice B is incorrect because area is 80. Choice C is incorrect because area is 72. Choice D is incorrect because perimeter would be 72.