Advanced Math practice question

Answer: 2

πr² = 2πr → r² = 2r → r = 2 (since r > 0).

Common wrong answers

If you answered 0

0 satisfies r² = 2r but is not a positive radius.

If you answered 1

1 gives area π and circumference 2π.

If you answered 4

4 gives area 16π and circumference 8π.

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