Examples with solutions for Circumference: Applying the formula

Exercise #1

Look at the circle in the figure:

444

Its radius is equal to 4.

What is its circumference?

Video Solution

Step-by-Step Solution

The formula for the circumference is equal to:

2πr 2\pi r

Answer

Exercise #2

O is the center of the circle in the figure below.

888OOO What is its circumference?

Video Solution

Step-by-Step Solution

We use the formula:P=2πr P=2\pi r

We replace the data in the formula:P=2×8π P=2\times8\pi

P=16π P=16\pi

Answer

16π 16\pi cm

Exercise #3

Look at the circle in the figure.

What is its circumference if its radius is equal to 6?

6

Video Solution

Step-by-Step Solution

Formula of the circumference:

P=2πr P=2\pi r

We insert the given data into the formula:

P=2×6×π P=2\times6\times\pi

P=12π P=12\pi

Answer

12π 12\pi

Exercise #4

Look at the circle in the figure.

The radius of the circle is 23 \frac{2}{3} .

What is its perimeter?

Video Solution

Step-by-Step Solution

The radius is a straight line that extends from the center of the circle to its outer edge.

The radius is essential for calculating the circumference of the circle, according to the following formula:

If we substitute the radius we currently have, the formula will be:

2*π*2/3

Let's start solving, we'll rearrange the formula:

π*2*2/3 =

We'll multiply the fraction by the whole number:

π*(2*2)/3 =

π*4/3 =

4/3π

And that's the result!

Answer

43π \frac{4}{3}\pi

Exercise #5

Given the circle whose radius has a length of 9 cm

999

What is its perimeter?

Video Solution

Answer

56.55

Exercise #6

A circle has a diameter of 12.

121212

What is its perimeter?

Video Solution

Answer

12π

Exercise #7

A circle has a radius of 3 cm.

What is its perimeter?

333

Video Solution

Answer

6π 6\pi cm

Exercise #8

O is the center of the circle in the diagram.

What is its perimeter?

444OOO

Video Solution

Answer

8π 8\pi cm

Exercise #9

Look at the circle in the figure.

Given that its radius is equal to 3, what is its circumference?

3

Video Solution

Answer

6π 6\pi

Exercise #10

Look at the circle in the figure below.555

The radius of the circle equals 5.

What is its perimeter?

Video Solution

Answer

10π 10\pi

Exercise #11

Look at the circle in the figure below.

The radius of the circle equals 7.

What is its perimeter?

777

Video Solution

Answer

14π 14\pi

Exercise #12

Look at the circle in the figure below.

The radius of the circle is equal to 8.

What is its perimeter?

888

Video Solution

Answer

16π 16\pi

Exercise #13

Look at the circle in the figure below.

The diameter of the circle is 4.

What is its perimeter?

444

Video Solution

Answer

4π 4\pi

Exercise #14

Look at the circle in the figure.

If its diameter is 5, then what is its circumference?

5

Video Solution

Answer

5π 5\pi

Exercise #15

Look at the circle in the figure.

The diameter of the circle is 10.

What is its perimeter?

101010

Video Solution

Answer

10π 10\pi

Exercise #16

Look at the circle in the figure.

The diameter of the circle is 12.

What is its perimeter?

121212

Video Solution

Answer

12π 12\pi

Exercise #17

r=11 r=11

Calculate the circumference.

111111

Video Solution

Answer

69.115

Exercise #18

r=7 r=7

Calculate the circumference.

777

Video Solution

Answer

43.982

Exercise #19

r=2 r=2

Calculate the circumference.

222

Video Solution

Answer

12.56

Exercise #20

r=6 r=6

Calculate the circumference.

666

Video Solution

Answer

37.699