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How To Find The Perimeter, Area, Circumference, Radius, and Diameter Of A Circle

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A circle has different parts and it is important to take know all the parts of the circle because, during calculations involving a circle, you would need them. In this article, we would give definitions of the perimeter, area, circumference, radius, and diameter of a circle, also, we would solve problems involving any of these parts.

Perimeter/Circumference Of a Circle

The perimeter of a circle is the distance around the circle and the term circumference is usually used instead of the perimeter but they represent the same thing.

Formula To Find The Circumference Of A Circle

The formula to find the circumference of a circle is πd or 2πr since d= 2r
π is a constant 22/7 OR 3.142
d is the diameter of a circle

The diagram shows the diameter and radius of a circle

Radius Of A Circle

The radius of a circle is the distance from the center of a circle to a point on the circumference of a circle. The radius of a circle must not necessarily be a straight line because many diagrams depict this, which has made people confused. The Radius of a circle is usually signified with small letter r

Diameter Of A Circle

The diameter of a circle is the distance from one point of the circumference to another point on the circumference. The diameter is twice the length of the radius hence the reason why diameter(D) is represented as 2r.

How To Find The Radius Of A Circle Given The Circumference

If you are given a question with the circumference and asked to find the radius of the circle, use the formula C=πd or 2πr and solve for r


Calculate the radius of a circle with a given circumference of 14cm


C = 2πr and this is equal to 14 = 2*22/7*r

Making r the subject of formula r = 14/6.28 now solving that with a calculator, you would get 2.227

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