# Question #e5881

##### 2 Answers

Jan 28, 2016

#### Answer:

See explanation..

#### Explanation:

Remember that

If diameter is

If

So,circumference of circle=

So,

So,circumference of circle=

This is a simple poof that i think is the best

Jan 28, 2016

#### Answer:

here is how you do it friend,

#### Explanation:

for this, we will need closed line integration.

suppose the radius of a circle is r

and after

so,

now,