Surface area and volume of spheres
key notes :
Volume of a sphere:
volume = 4/3 𝜋r3
Learn with an example
What is the volume of this sphere?
Use 𝜋 ≈ 3.14 and round your answer to the nearest hundredth.
__________ cubic metres.
Find the radius of the sphere.
radius = 7
Use this number in the volume formula. Use 𝜋 ≈ 3.14.
volume=4/3𝜋r3
≈4/3 . 3.14 . 73
≈1436.0266
Round your answer to the nearest hundredth:
1,436.0266 → 1,436.03
The volume of the sphere is about 1,436.03 cubic metres.
What is the volume of this sphere?
Use 𝜋 ≈ 3.14 and round your answer to the nearest hundredth.
___________ cubic centimetres.
Find the radius of the sphere.
radius = 2
Use this number in the volume formula. Use 𝜋 ≈ 3.14.
volume=4/3𝜋r3
≈4/3 . 3.14 . 23
≈33.4933
Round your answer to the nearest hundredth:
1,436.0266 → 1,436.03
The volume of the sphere is about 33.49 cubic centimetres.
What is the volume of this sphere?
Use 𝜋 ≈ 3.14 and round your answer to the nearest hundredth.
________ cubic millimetres.
Find the radius of the sphere.
radius = 3
Use this number in the volume formula. Use 𝜋 ≈ 3.14.
volume=4/3𝜋r3
≈4/3 . 3.14 . 33
≈113.04
The volume of the sphere is about 113.04 cubic millimetres.
let’s practice!
