The ring is equivalent to a hollow circle. The hollow circle has a small radius (R), and the whole circle has a large radius (R). The ring width is obtained by subtracting the radius of the hollow circle from the radius of the whole circle. Examples in life are hollow steel tubes, doughnuts, rings and so on, cutting part of a ring is called a fan ring.
Circumference of ring: circumference of outer circle + circumference of inner circle = Pi x (large diameter + small diameter) = π(D+D)
Ring area: outer circle area - inner circle area = circumference ratio × (square of large radius - square of small radius) = π(R×R-r×r)=π(R²-r²).
Enter any two conditions to find the inner diameter, outer diameter, width and area.
Select the exact number of digits: 4
Inner diameter: 5
External diameter: 8
Click "calculate" to output the result
Width: 1.5
Area: 30.63
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