Follow a worked example.
Every example below can be loaded using its calculator’s Reset example button. Inputs use centimetres, square centimetres or cubic centimetres as labelled, while angles use degrees.
Major and tube radii
Given: Major radius R = 6; Tube radius r = 2.
V = 2π²Rr²; S = 4π²Rr
| Measurement | Calculated value |
|---|---|
| Major radius R | 6 cm |
| Tube radius r | 2 cm |
| Outer radius | 8 cm |
| Hole radius | 4 cm |
| Volume | 473.74101 cm³ |
| Total surface area | 473.74101 cm² |
Outer radius and hole radius
Given: Outer radius = 8; Hole radius = 4.
R = (outer+hole)/2; r = (outer−hole)/2
| Measurement | Calculated value |
|---|---|
| Major radius R | 6 cm |
| Tube radius r | 2 cm |
| Outer radius | 8 cm |
| Hole radius | 4 cm |
| Volume | 473.74101 cm³ |
| Total surface area | 473.74101 cm² |
Surface area and major radius
Given: Surface area S = 473.741011252; Major radius R = 6.
r = S/(4π²R)
| Measurement | Calculated value |
|---|---|
| Major radius R | 6 cm |
| Tube radius r | 2 cm |
| Outer radius | 8 cm |
| Hole radius | 4 cm |
| Volume | 473.74101 cm³ |
| Total surface area | 473.74101 cm² |
Volume and major radius
Given: Volume V = 473.741011252; Major radius R = 6.
r = √[V/(2π²R)]
| Measurement | Calculated value |
|---|---|
| Major radius R | 6 cm |
| Tube radius r | 2 cm |
| Outer radius | 8 cm |
| Hole radius | 4 cm |
| Volume | 473.74101 cm³ |
| Total surface area | 473.74101 cm² |
Check the answer’s dimensions
An area contains a product of two lengths, while volume contains three. A perimeter or radius is still a length. If your input measurements are mixed between metres and centimetres, convert them to a common unit first. A realistic-looking number can still be wrong if the units were inconsistent.