# Circle

How big is area of circle if its circumference is 80.6 cm?

Result

S =  517 cm2

#### Solution:

$o = 2 \pi r = 80.6 \ \\ S = \pi r^2 \ \\ \ \\ S = \pi \left( \dfrac{ 80.6}{2\pi} \right)^2 = 517 \ cm^2$

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