You write 32/160 and simplify it. Then when your finished simplifying, you should get 1/5. 1/5, as you should all know, is also equivalent to 20%. Because 1/5 is 20% of 100.
You would start by multiplying the radius by its self to get 9.6 * 9.6= 92.16 then you would mutiply that by pie 92.16 * 3.14 = 289.38 and you would round that to 289.4
