Advanced MathEasyCoefficient of pi in a circle area
Advanced Math practice question
The area of a circle with radius r is πr². When r = 3, the area can be written as kπ. What is the value of k?
Answer: 9
π(3)² = 9π, so k = 9.
Common wrong answers
- If you answered 3
- 3 is r, not r².
- If you answered 6
- 6 is 2 × 3, using 2r instead of r².
- If you answered 28
- 28 rounds 9π itself; the question asks for the coefficient of π.
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