Circumference: Calculate The Missing Side based on the formula

A circle has a circumference of 31.41.

What is its radius?

To solve the exercise, first we must remember the circumference formula:

$P= 2\pi R$

P is the circumference and Pi has a value of 3.14 (approximately).

We substitute in the known data:

$31.41=2\cdot3.141\cdot R$

Keep in mind that the result can be easily simplified using Pi:

$\frac{31.41}{3.141}=2R$

$10=2R$

Finally, we simplify by 2:

$5=R$

5

A circle has a circumference of 50.25.

What is its radius?

We use the formula:

$P=2\pi r$

We insert the known data into the formula:

$50.25=3.14\times2r$

$50.25=2\times r\times3.14$

$50.25=6.28r$

$\frac{50.25}{6.28}=\frac{6.28r}{6.28}$

$r=8$

8

The circumference of a circle is 14.

How long is the circle's radius?

We begin by using the formula:

$P=2\pi r$

We then insert the given data into the formula:

$14=2\times\pi\times r$

Lastly we divide Pi by 2:

$\frac{14}{2\pi}=\frac{2\pi r}{2\pi}$

$\frac{7}{\pi}=r$

$\frac{7}{\pi}$

Calculate the radius using the circumference given in the figure:

63.662

Calculate the radius using the circumference given in the figure:

1.432

Calculate the radius using the circumference given in the figure:

12.732

Calculate the radius using the circumference given in the figure:

0.009

Calculate the radius based on the circumference given in the figure:

12.891

Calculate the radius using the circumference given in the figure:

5.666

Calculate the radius using the circumference given in the figure:

7.269

The circumference of a circle is equal to 8.

How long is its radius?

$\frac{4}{\pi}$

Given that the circumference of a circle is 20, what is the length of the circle's radius?

$\frac{10}{\pi}$

The circumference of a circle is 60.

What is the length of the radius of the circle?

$\frac{30}{\pi}$

The circumference of a circle is equal to 6.

What is the length of the radius of the circle?

$\frac{3}{\pi}$

If the circumference of a circle is equal to 18, then what is the length of its radius?

$\frac{9}{\pi}$

The circumference of a circle is equal to 14. How long is the circle's diameter?

$\frac{14}{\pi}$

The circumference of a circle is equal to 16.

What is the length of the circle's radius?

$\frac{8}{\pi}$

The circumference of a circle is equal to 100. What is the length of the radius of the circle?

$\frac{50}{\pi}$

Look at the circle in the figure.

What is its diameter?

$16$ cm

The circumference of a circle is equal to 30. What is the length of its radius?

$\frac{15}{\pi}$