Answer
a. $4390\ cm^2.$
b. $27,400\ cm^3.$
Work Step by Step
a. The area of the sphere is
$A=4\pi r^2=4 \pi (18.7)^2=4394.33\ cm^2\approx 4390\ cm^2.$
b. The volume of the sphere is
$V=\frac{4}{3}\pi r^3=\frac{4}{3} \pi (18.7)^3= 27391.34\ cm^3 \approx 27400\ cm^3.$
