Circumference: Calculate The Missing Side based on the formula

Increasing a specific element by addition of.....or multiplication by.......Using Pythagoras' theorem Verifying whether or not the formula is applicable Subtraction or addition to a larger shape A shape consisting of several shapes (requiring the same formula)Using variables Calculating parts of the circle Identifying and defining elements Using additional geometric shapes Worded problems Identify the greater value Finding Area based off Perimeter and Vice Versa Applying the formula

Question 1

A circle has a circumference of 31.41.

What is its radius?

Question 2

A circle has a circumference of 50.25.

What is its radius?

Question 3

The circumference of a circle is 14.

How long is the circle's radius?

Question 4

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

Question 5

Calculate the radius using the circumference given in the figure:

Examples with solutions for Circumference: Calculate The Missing Side based on the formula

Exercise #1

A circle has a circumference of 31.41.

What is its radius?

Video Solution

Step-by-Step Solution

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:

$5=R$

Answer

Exercise #2

A circle has a circumference of 50.25.

What is its radius?

Video Solution

Step-by-Step Solution

We use the formula:

$P=2\pi r$

We insert the known data into the formula:

$50.25=3.14\times2r$

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

$50.25=6.28r$

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

$r=8$

Answer

Exercise #3

The circumference of a circle is 14.

How long is the circle's radius?

Video Solution

Step-by-Step Solution

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:

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

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

Answer

$\frac{7}{\pi}$

Exercise #4

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

Video Solution

Answer

12.891

Exercise #5

Calculate the radius using the circumference given in the figure:

Video Solution

Answer

1.432

Question 1

Calculate the radius using the circumference given in the figure:

Question 2

Calculate the radius using the circumference given in the figure:

Question 3

Calculate the radius using the circumference given in the figure:

Question 4

Calculate the radius using the circumference given in the figure:

Answer

12.732

Question 1

Look at the circle in the figure.

What is its diameter?

Question 2

What is the radius of a circle with a circumference of $8\pi$ cm?

Question 3

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

Question 4

The circumference of a circle is equal to 16.

What is the length of the circle's radius?

Question 5

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

Exercise #11

Exercise #14

The circumference of a circle is equal to 16.

What is the length of the circle's radius?

Video Solution

Answer

$\frac{8}{\pi}$

Exercise #15

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

Video Solution

Answer

$\frac{10}{\pi}$

Question 1

The circumference of a circle is 4.

How long is the radius of the circle?

Question 2

The circumference of a circle is equal to 6.

What is the length of the radius of the circle?

Question 3

The circumference of a circle is equal to 8.

How long is its radius?

Question 4

The circumference of a circle is 60.

What is the length of the radius of the circle?

Answer

$\frac{30}{\pi}$

Exercise #20

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

Video Solution

Answer

$\frac{9}{\pi}$