If the perimeter and the area of a circle are numerically equal, what is the radius of the circle?
Answer and explanation
Correct answer: A.
- Step 1: Express perimeter (circumference) and area using radius : Perimeter , and Area .
- Step 2: Set them numerically equal: . Dividing both sides by (since radius ) yields .
Answer
.
Why not the others: '' incorrectly equates to the constant ; '' squares the correct radius; '' confuses radius with circumference approximation.
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