sphere problem 1:
A = 4 * r² * π
A = 4 * 8² * π
A = 804.25 cm².
A: The surface area is 804.25 cm².
answer volume:
V = 4 * r³ * π : 3
V = 4 * 8³ * π : 3 (π = 3.1415..)
V = 2 144.66 cm³
A: The volume is 2 144.66 cm³.
sphere problem 2:
A sphere has a diameter of 12 cm.
a) calculate the surface area
b) calculate the volume
answer surface area:
radius = diameter : 2
radius = 12 : 2
radius = 6 cm
A = 4 * r² * π
A = 4 * 6² * π
A = 452.39 cm².
A: The surface area is 452.39 cm².
answer volume:
V = 4 * r³ * π : 3
V = 4 * 6³ * π : 3
V = 904.78 cm³
A: The volume is 904.78 cm³.
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.
sphere problem 4:
answer radius:
V = 4 * r³ * π : 3
104 = 4 * r³ * π : 3 / * 3
312 = 4 * r³ * π / : 4
78 = r³ * π / : π
24,282…. = r³ / ³√
r = 2.92 cm.
A: The radius is 2.92 cm.
answer surface area:
A = 4 * r² * π
A = 4 * 2.92² * π
A = 107.15 cm²
A: The surface area is 107.15 cm².