jeremy is making a circular , birthday cake and knows that he used exactly 47.1 cm of ribbon to go round the cake . calculate the area on top of the cake that requires decoration (use pi 3.14)
Since the 47.1 cm is the circumference of a circle, we can find the radius thusly:
47.1 = 2 * 3.14 * r = 6.28 r solve for r
r = [ 47.1 / 6.28 ] cm
So....the area covered is =
pi * r^2 =
3.14 * [ 47.1 / 6.28]^2 = about 176.63 cm^2
