The total area covering the curved outer surface of a sphere, given by the formula S=4πr2.
The 'skin area' of a perfectly round ball—the amount of material needed to cover it with no overlaps.
Showing a random 20 of 50 problems.
Example 1
hard
A spherical tank has surface area 400π ft2. How many gallons does it hold? (1 ft3≈7.48 gal.)
Example 2
medium
Why does a sphere have the smallest surface area for a given volume?
Example 3
easy
Find the surface area of a sphere with radius 4 in terms of π.
Example 4
challenge
A sphere and a cube have equal surface areas. The sphere has radius 3. Find the cube's edge length (use π≈3.14).
Example 5
easy
What is the formula for the surface area of a sphere?
Example 6
medium
Spherical bearing has surface area 16π mm2. What is its diameter?Sphere with surface area 16π mm² — find its diameter
Example 7
medium
Two spheres have radii 3 and 6. Find the ratio of their surface areas.
Example 8
easy
Find the surface area of a sphere with radius 7 cm.Sphere with radius 7 cm — find its surface area
Example 9
challenge
Why do small water droplets form near-perfect spheres, in terms of surface area and energy?
Example 10
easy
If a sphere's radius doubles, its surface area multiplies by what factor?
Example 11
easy
Find the surface area of a sphere with radius 3 in terms of π.Sphere with radius 3 — find its surface area in terms of π
Example 12
hard
If a sphere's radius increases by 50%, by what percent does its surface area increase?
Example 13
hard
Two spheres have radii in the ratio 2:3. Find the ratio of their surface areas. If the smaller sphere has a surface area of 64π cm², find the surface area of the larger sphere.
Example 14
easy
Find the curved surface area of a hemisphere with radius 8, in terms of π.
Example 15
easy
Find the surface area of a sphere with radius 5 in terms of π.Sphere with radius 5 — find its surface area in terms of π
Example 16
medium
A sphere has a surface area of 100π cm². Find its radius and volume.
Example 17
medium
A sphere has surface area S. Express its radius in terms of S.
Example 18
easy
A basketball has a diameter of 24 cm. Find its surface area.
Example 19
medium
A sphere has surface area 144π. Find its volume in terms of π.
Example 20
medium
A sphere is inscribed in a cube of side 8. Find the sphere's surface area in terms of π.