Annulus (ring)
Area and perimeter of an annulus (ring).
Diagram
Enter values
Enter the shape's values – area, perimeter and the drawing update instantly.
Area and perimeter
Area (denoted S) is the size of the surface inside a shape, measured in square units (cm², m²…). Perimeter (o) is the length of the boundary all the way around, measured in length units (cm, m…). The calculator above computes both and draws the shape.
Tip: entered values are saved on this device, so you'll find them filled in when you return.