Question

The circumference of a standard bowling ball is about 27 in. To the nearest unit, how many square inches is the surface area of 100 bowling balls? Explain.

Answer 1

The surface area of a sphere is $S=4 \pi r^{2}$ where r is the radius;
The circumference is $2 \pi r=27 in$ so that $r= \frac{27}{2 \pi }=4.5 in$ using this value we can evaluate the surface area of 1 ball as:
$S=4 \pi r^{2} =4 \pi (4.5)^{2} =254.3 in^{2}$
For 100 ball you get: $100*254.3=25430 in^{2}$