A rectangle has perimeter 40. What is the largest area it can have?
Answer and explanation
Correct answer: C.
- Step 1: If one side is , the other is , so the area is . Step 2. This parabola has its maximum at , where the area is . **Answer: . Why not the others:** and are the areas of the rectangles and , which are smaller, and squares the semi-perimeter 20.
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