High School Math : How to find the circumference of a circle in pre-algebra

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #11 : How To Find The Circumference Of A Circle In Pre Algebra

What is the circumference of a circle with a radius of ?

Possible Answers:

Correct answer:

Explanation:

The formula for circumference of a circle is .

Plug in our given values.

Example Question #12 : How To Find The Circumference Of A Circle In Pre Algebra

What is the circumference of a circle with a radius of ?

Possible Answers:

Correct answer:

Explanation:

The formula for the circumference is .

Plug in our given radius and solve.

Example Question #13 : How To Find The Circumference Of A Circle In Pre Algebra

What is the circumference of a circle with a radius of ?

Possible Answers:

Correct answer:

Explanation:

To find the circumference of a circle given the radius we must first know the equation for the circumference of a circle which is 

We then plug in the number for the radius into the equation yielding

 

We multiply to find the value for the circumference is .

The answer is .

Example Question #11 : How To Find The Circumference Of A Circle In Pre Algebra

What is the circumference of a circle with a radius of ?

Possible Answers:

Correct answer:

Explanation:

To find the circumference of a circle we must first know the equation for the circumference of a circle, which is .

We then plug in the given value for the radius, yielding .

We multiply to find the value for the circumference is .

Thus answer is .

Example Question #11 : How To Find The Circumference Of A Circle In Pre Algebra

What is the circumference of a circle with a radius of ?

Possible Answers:

Correct answer:

Explanation:

To find the circumference of a circle given the radius, we must first know the equation for the circumference of a circle which is

We then plug in  for the radius into the equation yielding 

We multiply to find the value for the circumference is

The answer is .

Example Question #12 : How To Find The Circumference Of A Circle In Pre Algebra

Find the circumference of a circle with a diameter of 4 meters. 

Possible Answers:

 meters 

 meters 

 meters 

 meters

 meters 

Correct answer:

 meters 

Explanation:

The formula for circumference is: 

 where  is the radius of our circle 

In this case, we were given the diameter of  meters. Thus, we know that the radius is  meters (since the diameter is twice the radius). Plugging this into the formula, we have: 

 meters. 

Example Question #13 : How To Find The Circumference Of A Circle In Pre Algebra

What is the circumference of a circle with a radius of ?

Possible Answers:

Correct answer:

Explanation:

The formula for the circumference of a circle is .

Plug in our given values and solve.

Example Question #14 : How To Find The Circumference Of A Circle In Pre Algebra

What is the circumference of a circle with a radius of ?

Possible Answers:

Correct answer:

Explanation:

To find the circumference of a circle, use the equation:

Substitute the given value for the radius into the equation:

Example Question #15 : How To Find The Circumference Of A Circle In Pre Algebra

An ant is standing at the center of a perfectly circular plate. If the ant crawled in a straight line, he would have to crawl 6 inches to reach the edge of the plate. How many inches would he crawl if he crawled a full circle around the edge of the plate?

Possible Answers:

Correct answer:

Explanation:

We need to find the circumference:

In this formula  stands for the radius and  stands for the diameter. 

The distance the ant must crawl to the edge from the center is the radius of the circle.

Plug in 6 inches for :

Example Question #16 : How To Find The Circumference Of A Circle In Pre Algebra

If a circle has a radius of meters, what is its circumference? 

Possible Answers:

Correct answer:

Explanation:

The formula for the circumference of a circle is , where  is the diameter. This can also be written as , where  is the radius of the circle. We were given the radius, so we take the second formula and plug in  for .

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