Circle circumference — lesson. Mathematics CBSE, Class 7.

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All circles are similar to one another. So, the ratio of the circumference to that of diameter is a constant,

That is

$\frac{Circumference}{Diameter} = constant$ (pi

$π$ )

Therefore

$\frac{C}{d} = π$ (Where the approximate value of

$π$ is

$3.14$ )

$C$

$=$

$d \cdot π$ or

$C$

$=$

$d \cdot 3.14$

The diameter is twice the radius (

$2r$ ), so the above equation can be
written as

$C = 2r \cdot π$ Note: $d\$

$=$

$2r$

Therefore, the circumference of a circle,

$C = 2$

$π$

$r$ units.

Did you find an error?

4. Circle circumference