A rectangle has perimeter 40 cm. What is the maximum possible area?
Answer and explanation
Correct answer: D. 100 cm
- Step 1: Let the sides be and , so .
- Step 2: gives .
- Step 3: , so a maximum: .
Answer
100 cm.
Why not the others: 200 cm: the perimeter 40 was treated as length plus width (20 × 10). 75 cm: a non-optimal width of 5 cm was used. 400 cm: each side was taken as 20 cm.
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