<h2 dir="ltr">What is a Circle?</h2>
A circle is the simplest closed curve, lying in a plane. A circle can be defined as a set of every point in a plane that is equidistant from a given central point. The fixed distance of such points from the center is called the radius, r, of the circle, while the point is called the center.. Diameter (d) is the line segment that passes through the center of the circle and touches two points on the boundary, which is also called the circumference.
<h2 dir="ltr">Formulas Related to Circles</h2>
The Formulas of Circle are given as,
<h3 dir="ltr">1. Diameter</h3>
The diameter is the longest distance across the circle, passing through the middle.
&nbsp;&nbsp;&nbsp;&nbsp;D = 2r
where, r is the radius.
<h3 dir="ltr">2. Circumference</h3>
The circumference is the distance around the circle.
C = 2&pi;r<img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXfFe_TJ0FaK59YeFkYZyZxUjsfVXdJho1OTZJ0i_kBDJ0iayLDxWdHVE5iH3q2X6OJ31F3fBRN121ob062h1MTuL2C16SkcvZikfJH-Q1sZ49mwJimz76L6P3KRhPILMN7dIt6MOQ5q3OPhINikIgr3yNjl?key=hMczyPsuSqOA_KnEBbIARg" width="89" height="21">
where, r is the radius &amp;&nbsp;
3. Area
The area is the space enclosed within the circle.
<img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXcle2CiC4lnI7ng3g0MtDQ_d-EG6j5LoMTwYXnBCp61u2fOhpSn_gL1rG95nrEYBJwwPEPm6Um_FkYXGif4v1Xa8tHzpFPUp_XU2EwDuyWaXyybPIbL7Kqn60cWOctLUggOE9M2jAbsVFLn1uWqyohVC9c?key=hMczyPsuSqOA_KnEBbIARg" alt="circle formula" width="73" height="26">
where r is the radius.
<h2 dir="ltr">Solved Problems</h2>
Problem 1: A circle has a radius 8 cm. Calculate its diameter, area and circumference.
Solution:
Given parameters are,
&nbsp;Radius, r = 8cm
Diameter of a circle is given by
&nbsp;D =2r
&nbsp;&nbsp;&nbsp;&nbsp;= 2 &times; 8 cm
&nbsp;&nbsp;&nbsp;&nbsp;= 16 cm
Area of a circle,
<img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXcle2CiC4lnI7ng3g0MtDQ_d-EG6j5LoMTwYXnBCp61u2fOhpSn_gL1rG95nrEYBJwwPEPm6Um_FkYXGif4v1Xa8tHzpFPUp_XU2EwDuyWaXyybPIbL7Kqn60cWOctLUggOE9M2jAbsVFLn1uWqyohVC9c?key=hMczyPsuSqOA_KnEBbIARg" alt="circle formula" width="73" height="26">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;= &pi; &times; 64
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;= 201.088 cm2
Circumference of a circle,
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;C =2 &pi; r
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;= 2 &times; &pi; &times; 8
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;= 50.272 cm
Problem 2: Find diameter, area and circumference of a circle of radius 15 cm.
Solution:
Given parameters are,
Radius of a circle, r = 15 cm
Diameter of a circle,
&nbsp;&nbsp;&nbsp;D = 2r
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;= 2 &times; 15
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;= 30 cm
Area of a circle ,
<img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXcle2CiC4lnI7ng3g0MtDQ_d-EG6j5LoMTwYXnBCp61u2fOhpSn_gL1rG95nrEYBJwwPEPm6Um_FkYXGif4v1Xa8tHzpFPUp_XU2EwDuyWaXyybPIbL7Kqn60cWOctLUggOE9M2jAbsVFLn1uWqyohVC9c?key=hMczyPsuSqOA_KnEBbIARg" alt="circle formula" width="73" height="26">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXdOy_nzU3OOOkZsrLFHnRKv9kDpVgHja8ma6xphpVP6C_zFYUiIIAY0t1sBCpWih2OgkhcBsi78O1xxY0W6Psyskns81IlmrIZQF4D9jgzcfe6P6z4Hi2CWkXtdUpCX9-lEikcZzZoG0VKpVko62WnAxy5W?key=hMczyPsuSqOA_KnEBbIARg" width="66" height="24">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;= &pi; &times; 225
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<img src="https://lh7-rt.googleusercontent.com/docsz/AD_4nXeGMc_qNQ81syYwIT0szi90ByzcWO7Imph967j4olJzUEqq33ZZwmHTaKIfH8iP2PWXl5sVuEfGPmiQ6-bMAYeDRfeznSgiuhIBsys1C0SbFqMcm-4y85Eqpw-62n4HMmjs5VmjHLCBZwYxTkRYOxsXUPsm?key=hMczyPsuSqOA_KnEBbIARg" width="27" height="20">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;= 706.95&nbsp;
Circumference of a circle,
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;C = 2 &pi; r
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;= 2 &times; &pi; &times; 15
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;= 94.26 cm
&nbsp;
Other Related Sections
<a href="https://www.orchidsinternationalschool.com/ncert-solutions" target="_blank" rel="noopener">NCERT Solutions</a> |<a href="https://www.orchidsinternationalschool.com/sample-paper" target="_blank" rel="noopener"> Sample Papers</a> |<a href="https://www.orchidsinternationalschool.com/cbse-syllabus" target="_blank" rel="noopener"> CBSE SYLLABUS</a>|<a href="https://www.orchidsinternationalschool.com/calculators" target="_blank" rel="noopener"> Calculators</a> |<a href="https://www.orchidsinternationalschool.com/converters" target="_blank" rel="noopener"> Converters</a> |<a href="https://www.orchidsinternationalschool.com/story" target="_blank" rel="noopener"> Stories For Kids</a> |<a href="https://www.orchidsinternationalschool.com/poems" target="_blank" rel="noopener"> Poems for kids</a>| <a href="https://www.orchidsinternationalschool.com/concepts" target="_blank" rel="noopener">Learning Concepts</a> I <a href="https://www.orchidsinternationalschool.com/worksheets" target="_blank" rel="noopener">Practice Worksheets</a> I <a href="https://www.orchidsinternationalschool.com/formula" target="_blank" rel="noopener">Formulas </a>| <a href="https://www.orchidsinternationalschool.com/blog" target="_blank" rel="noopener">Blogs</a> | <a href="https://www.orchidsinternationalschool.com/parent-resources">Parent Resource</a>

Circle Formula

Understand what is the Circle, Learn about the Circle Formula in physics, and get the solved examples at Orchids International School.