The area of a square is 49cm^2. The perimeter of the square is equal to the circumference of a circle. what is the radius of the circle?

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This is a geometry question. 

We know that a square has 4 equal sides of x, and that it's area is given by A=x2

So we can work out the length of the side of the square. 

x=sqrt(49) = 7

We are told this is equal to the circumference of the circle.

The equation for circumference of a circle is, c=2πr 

We need to find r, so we can rearrange this to give; r = c / 2π

Substituting in the value for c =49 cm

we get r = 49 / 2π  = 7.80 cm

*Don't forget units! 

Julia C. GCSE Chemistry tutor, A Level Chemistry tutor, 13 plus  Math...

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