Table of Contents
Definition
A sphere is a perfectly round geometrical object in 3D space that is the surface of a completely round ball.
Sphere Facts
Here are some interesting facts about sphere:
- It is perfectly symmetrical
- All points on the surface are the same distance “r” from the center
- It has no edges or vertices (corners)
- It has one surface (not a face as it isn’t flat)
- It is not a polyhedron
Volume and Surface Area
Surface Area = 4 × π × r2
Volume = (4/3) × π × r3
Example
r = 21 cm
| Surface Area | Volume |
| Surface Area = 4 × π × r2 Surface Area = 4 × 22/7 × (21 cm)2 Surface Area = 5544 cm2 | Volume = (4/3) × π × r3 Volume = 4/3 × 22/7 × (21 cm)3 Volume = 38808 cm3 |