A spherical zone or a frustum of a sphere is the portion of a sphere that's been cut by two parallel planes. The surface area of a spherical zone or a frustum of a sphere is the sum of the areas of the circular top and bottom disks plus the lateral curved area.

The shape of a spherical zone is similar to a portion of a fruit, such as a watermelon or cantaloupe, that has been cut by two parallel slices. Other examples of objects that have a similar shape include certain types of lamps, decorative objects, and architectural elements such as domes, arches and camera lenses.

Easily calculate the surface area of a spherical zone with step-by-step guidance using our free calculator below.

The formula for determining the surface area of a spherical zone is defined as:

Use this calculator to determine the surface area of a spherical zone or a frustum of a sphere using the height of the zone and the radii of both the top and bottom disks.

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the radius of the top disk

\(r_1\)

\(meter\)

the radius of the bottom cap

\(r_2\)

\(meter\)

the distance between the top and bottom caps

\(h\)

\(meter\)

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