Formula
The sphere's surface is four times the area of a circle with the same radius:
Surface area = 4 × π × radius²
The circle page is the flat disk. This page is the closed surface.
Assumptions
- The radius reaches from the center to the surface.
- The sphere is complete.
Worked example
A sphere with radius 3 has surface area 113.1.
Input definitions
- Radius
- The distance from the center to the surface.
Limitations
The result is rounded to two decimal places.
Questions
Is this body surface area?
No. That is a health estimate. This is the geometry of a sphere.
How is it different from a circle?
A circle's area is πr². A sphere's surface is four times that.