Question 829767
Do you remember how to find the area of a circle?
Pi * r^2
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Hannah's circle has a radius of 30cm.  30cm * 30cm = 900 cm^2.
Multiply that by pi (we'll use 3.14) to get 2826 cm^2
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Jonas' circle has a radius of 20cm.  Let's square that.  20cm * 20cm = 400cm^2.
Multiply that by pi to get 1256 cm^2.
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Now it's simple subtraction.  2826 - 1256 = 1570cm^2