How to calculate Circumference, Diameter, Area, and Radius

The circle calculator find the area, radius, diameter and also circumference that a one labeled together a, r, d and c respectively.

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For those having an obstacle using formulas manually to find the area, circumference, radius and diameter the a circle, this one calculator is just for you. The equations will certainly be given listed below so you have the right to see exactly how the calculator obtains the values, yet all you need to do is entry the straightforward information. The calculator does the rest.


Finding the Circumference:

The one is comparable to the perimeter in the it is the complete length necessary to attract the circle.

We note the circumference together c.

c = 2πr


c = πd

This depends on whether or not you understand the radius (r) or the diameter (d)

Let’s calculate one manually, because that example.

If r = 6 cm, the the one is c = 2π(6) = 12π cm, if composing in terms of π. If you choose a number value, the prize rounded come the nearest tenth is 37.7 cm.

Suppose you only understand the diameter? If the diameter is 8 cm, climate the one is c = π(8) = 8π or 25.1 cm, rounded come the nearest tenth.

A an excellent thing around the formulas is the you deserve to manipulate that to solve for one unknown if you know one the the various other quantities. For example, if we know the circumference, yet don’t know the radius, you can solve c = 2πr for r and also get \\(r = \\fracc2\\pi\\). Similiarly, if you desire the diameter from the circumference, simply take c =πd and solve for d to acquire d = \\(\\fracc\\pi\\).


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Finding the Area:

Let a = area that the circle

a = πr²

If you recognize the diameter and also not the radius, just divide the diameter by 2 to get the radius and also still usage the formula above.

Again, the formula have the right to be provided to resolve for the radius, if you recognize the area. Simply divide a through π to acquire r² and also take the square source of the result.

If you great to understand the diameter from the area, follow the procedure above but dual the result you get for r. This is because the diameter is double the size of the radius.

Try an example manually to acquire the area.

Suppose r = 5 inches

a = πr²

a = π(25) = 25π

If rounding to the nearest tenth the area is 78.5 square inches.

If you recognize the diameter, just divide through 2 to gain the radius and also use the exact same formula as above.

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Of course, you don’t need to go v all the hand-operated calculations to usage this calculator. Simply input the info you know and also the remainder will be computed for you almost instantly.