s=Пr^2 r=d/2 r=6.5
s=П*(6.5)^2=П42.25
5 * (2 + 4 + 1* 2 * 7) = 100
5 * (2 + 4 + 1* 2 * 7) = 5 * ( 6 + 14) = 5 * 20 = 100