Sphere — Grade 8 Math, what it means and where it is taught
A ball. V = 43π r3.
Taught in Grade 8 Math.
Where it is taught
What it rests on
Work through these first if this one does not settle.
- π — The circumference of any circle divided by its diameter — about 3.14159.
Practise this idea
6 questions in the course bank use Sphere, in Volume of Cylinders, Cones & Spheres, Solids: Volume, Sections & Rotations.
Problem 1
Find the volume of a sphere with r = 3, in terms of π.
Worked answer
36pi
33 = 27
43π(27) = 36π
Problem 2
Find the volume of a sphere with diameter 6, in terms of π.
Worked answer
36pi
r = 3
43π(27) = 36π
Problem 3
A sphere has volume 256π3. Find its radius.
Worked answer
4
43r3 = 2563
4r3 = 256
r3 = 64, so r = 4
Problem 4
A cylindrical glass of radius 4 and height 12 is filled, then a sphere of radius 3 is dropped in. How much water in terms of π overflows?
Worked answer
36pi
Sphere: 43π(27) = 36π
The glass was already full
So 36π overflows
Problem 5
Find the volume of a sphere with r = 3, in terms of π.
Worked answer
36pi
43 π (27) = 36π
Problem 6
Find the surface area of a sphere with r = 6, in terms of π.
Worked answer
144pi
4π(36) = 144π