Geometry
Surface area to volume ratio
Falls as the sphere grows, which is why large bodies retain heat and small ones lose it quickly.
The Formula
A / V = 3 / r
Falls as the sphere grows, which is why large bodies retain heat and small ones lose it quickly.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| A | Surface area | square metres | Outside area. |
| V | Volume | cubic metres | Enclosed space. |
| r | Radius | metres | Centre to surface distance. |
What Each Symbol Means
Asquare metres
Surface area
Outside area.
Vcubic metres
Volume
Enclosed space.
rmetres
Radius
Centre to surface distance.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate the surface area of a sphere page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate The Surface Area Of A Sphere, filed under Math. Every number the guide produces comes from substituting into this one line.