sphere problem 3:
The surface area of a sphere is 76.8 cm².
a) calculate the radius
b) calculate the volume
answer radius:
A = 4 * r² * π
76.8 = 4 * r² * π / : 4
19,2 = r² * π / : π
6,11.. = r² / √
r = 2.47 cm.
A: The radius is 2.47 cm.
answer volume:
V = 4 * r³ * π : 3
V = 4 * 2.47³ * π : 3
V = 63.12 cm³
A: The volume is 63.12 cm³.