This annulus (ring) reference table shows the ring area for a range of outer radius (r) values, assuming an inner radius (r) of 5 units. Every figure is computed with the same engine that powers our Annulus (Ring) Calculator, so the numbers are exact.
| Outer radius (R) | Ring area | Ring width |
|---|---|---|
| 2 units | -65.9734 | -3.0000 |
| 4 units | -28.2743 | -1.0000 |
| 6 units | 34.5575 | 1.0000 |
| 8 units | 122.5221 | 3.0000 |
| 12 units | 373.8495 | 7.0000 |
| 16 units | 725.7079 | 11.0000 |
| 24 units | 1,731.0176 | 19.0000 |
| 40 units | 4,948.0084 | 35.0000 |
| 56 units | 9,773.4947 | 51.0000 |
| 80 units | 20,027.6532 | 75.0000 |
How to use this table
Find the row closest to your outer radius (r) and read across to the ring area. For a value between two rows, the real figure sits between them — or enter your exact numbers in the Annulus (Ring) Calculator for a precise answer.
Need a value that is not in the table? — the Annulus (Ring) Calculator does it instantly, for free, with the formula and a worked example built in.
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