Call Now to Set Up Tutoring:

(888) 888-0446

ISEE Upper Level Math : Radius

Study concepts, example questions & explanations for ISEE Upper Level Math

Create An Account

All ISEE Upper Level Math Resources

6 Diagnostic Tests 244 Practice Tests Question of the Day Flashcards Learn by Concept

Example Questions

Example Question #1 : Radius

What is the radius of a circle with circumference equal to $36\pi$ ?

Possible Answers:

r=18

r=3

r=9

r=6

Correct answer:

r=18

Explanation:

The circumference of a circle can be found using the following equation:

$C=d\pi=2r\pi$

$36\pi=2r\pi$

$\frac{36\pi}{\pi}=\frac{2r\pi}{\pi}$

36=2r

$\frac{36}{2}=\frac{2r}{2}$

18=r

Report an Error

Example Question #1 : Radius

What is the value of the radius of a circle if the area is equal to $18\pi$ ?

Possible Answers:

$2\sqrt{3}$

$3\sqrt{2}$

Correct answer:

$3\sqrt{2}$

Explanation:

The equation for finding the area of a circle is $\pi r^{2}$ .

Therefore, the equation for finding the value of the radius in the circle with an area of $18\pi$ is:

$\pi r^{2}=18\pi$

$r^{2}=18$

$r=\sqrt{18}=\sqrt{9\cdot 2}=3\sqrt{2}$

Report an Error

Example Question #2 : Radius

What is the radius of a circle with a circumference of $24\pi$ ?

Possible Answers:

r=10

r=8

r=12

r=9

r=24

Correct answer:

r=12

Explanation:

The circumference of a circle can be found using the following equation:

$C=2r\pi$

We plug in the circumference given, $24\pi$ into and use algebraic operations to solve for .

$24\pi=2r\pi$

$\frac{24\pi }{\pi }=\frac{2r\pi }{\pi }$

24=2r

$\frac{24}{2}=\frac{2r}{2}$

r=12

Report an Error

Example Question #2 : How To Find The Length Of A Radius

Inscribed angle

Refer to the above diagram. $\overarc {ACB}$ has length $60 \pi$ . Give the radius of the circle.

Possible Answers:

100

Correct answer:

Explanation:

Inscribed $\angle ACB$ , which measures $72 ^{\circ }$ , intercepts a minor arc with twice its measure. That arc is $\overarc {AB}$ , which consequently has measure

$72 ^{\circ } \times 2 = 144 ^{\circ }$ .

The corresponding major arc, $\overarc {ACB}$ , has as its measure

$360 ^{\circ } - 144 ^{\circ } = 216 ^{\circ }$ , and is

$\frac{ 216 }{360 } = \frac{ 216 \div 72 }{360 \div 72 } = \frac{3}{5}$

of the circle.

If we let be the circumference and be the radius, then $\overarc {ACB}$ has length

$\frac{3}{5} C = \frac{3}{5} \cdot 2 \pi r = \frac{6 \pi}{5} r$ .

This is equal to $60 \pi$ , so we can solve for in the equation

$\frac{6}{5} \pi r = 60 \pi$

$\frac{5}{6 \pi } \cdot \frac{6 \pi }{5} r = \frac{5}{6 \pi } \cdot 60 \pi$

r = 50

The radius of the circle is 50.

Report an Error

Example Question #3 : How To Find The Length Of A Radius

A circle has a circumference of $768\pi m$ . What is the radius of the circle?

Possible Answers:

384 m^2

384 m

125 m

Not enough information to determine.

Correct answer:

384 m

Explanation:

A circle has a circumference of $768\pi m$ . What is the radius of the circle?

Begin with the formula for circumference of a circle:

$Circumference=2\pi r$

Now, plug in our known and work backwards:

$768\pi m=2\pi r$

Divide both sides by two pi to get:

384m=r

Report an Error

Example Question #2 : How To Find The Length Of A Radius

You are exploring the woods near your house, when you come across an impact crater. It is perfectly circular, and you estimate its area to be $169 \pi m^2$ .

What is the radius of the crater?

Possible Answers:

Cannot be determined from the information provided

26m

15.5m

13m

Correct answer:

13m

Explanation:

You are exploring the woods near your house, when you come across an impact crater. It is perfectly circular, and you estimate its area to be $169 \pi m^2$ .

What is the radius of the crater?

To solve this, we need to recall the formula for the area of a circle.

$A=\pi r^2$

Now, we know A, so we just need to plug in and solve for r!

$169 \pi m^2=\pi r ^2$

Begin by dividing out the pi

169m^2=r^2

Then, square root both sides.

$r=\sqrt{169m^2}=13m$

So our answer is 13m.

Report an Error

Example Question #1 : Area Of A Circle

What is the area of a circle that has a diameter of inches?

Possible Answers:

706.8583

153.938

176.7146

940

153.938

940

960

Correct answer:

176.7146

Explanation:

The formula for finding the area of a circle is $\pi r^{2}$ . In this formula, represents the radius of the circle. Since the question only gives us the measurement of the diameter of the circle, we must calculate the radius. In order to do this, we divide the diameter by .

$\frac{15}{2}=7.5$

Now we use 7.5 for in our equation.

$\pi (7.5)^{2}=176.7146 \: in^{2}$

Report an Error

Example Question #122 : Area

What is the area of a circle with a diameter equal to 6?

Possible Answers:

$18\pi$

$3\pi$

$9\pi$

$36\pi$

Correct answer:

$9\pi$

Explanation:

First, solve for radius:

$r=\frac{d}{2}=\frac{6}{2}=3$

Then, solve for area:

$A=r^2\pi=3^2\pi=9\pi$

Report an Error

Example Question #3 : Radius

The diameter of a circle is $4\ cm$ . Give the area of the circle.

Possible Answers:

$12.56\ cm^2$

$12 \ cm^2$

$11.56\ cm^2$

$13.56\ cm^2$

$13\ cm^2$

Correct answer:

$12.56\ cm^2$

Explanation:

The area of a circle can be calculated using the formula:

$Area=\frac{\pi d^2}{4}$ ,

where is the diameter of the circle, and $\pi$ is approximately 3.14 .

$Area=\frac{\pi d^2}{4}=\frac{\pi\times 4^2}{4}=4\pi \Rightarrow Area\approx 4\times 3.14\Rightarrow Area\approx 12.56 \ cm^2$

Report an Error

Example Question #4 : Know And Use The Formulas For The Area And Circumference Of A Circle: Ccss.Math.Content.7.G.B.4

The diameter of a circle is . Give the area of the circle in terms of .

Possible Answers:

11.56 t

12.56 t^2

11.56 t^2

12.56 t

12 t^2

Correct answer:

12.56 t^2

Explanation:

The area of a circle can be calculated using the formula:

$Area=\frac{\pi d^2}{4}$ ,

where is the diameter of the circle and $\pi$ is approximately 3.14 .

$Area=\frac{\pi (4t)^2}{4}=\frac{16\pi t^2}{4}=4\pi t^2 \Rightarrow Area\approx 4\times 3.14\times t^2$

$\Rightarrow Area\approx 12.56t^2$

Report an Error

View Tutors

Yongmao
Certified Tutor

Nankai University, Bachelor of Science, Chemistry. Washington University in St Louis, Doctor of Philosophy, Organic Chemistry.

View Tutors

Bagher
Certified Tutor

San Jose State University, Master's/Graduate, Physics.

View Tutors

Sumit
Certified Tutor

Calcutta University, Bachelor of Science, Mathematics. Indian Statistical Institute, Master of Science, Mathematics.

All ISEE Upper Level Math Resources

6 Diagnostic Tests 244 Practice Tests Question of the Day Flashcards Learn by Concept

Popular Subjects

Statistics Tutors in Seattle, Reading Tutors in Boston, LSAT Tutors in Phoenix, Math Tutors in Philadelphia, Computer Science Tutors in Denver, Chemistry Tutors in Miami, Algebra Tutors in Chicago, ISEE Tutors in Chicago, ISEE Tutors in Seattle, Computer Science Tutors in Miami

Popular Courses & Classes

ACT Courses & Classes in Atlanta, GMAT Courses & Classes in Miami, ACT Courses & Classes in Boston, LSAT Courses & Classes in Los Angeles, ACT Courses & Classes in New York City, Spanish Courses & Classes in Houston, SAT Courses & Classes in Seattle, GRE Courses & Classes in Miami, ISEE Courses & Classes in Dallas Fort Worth, Spanish Courses & Classes in New York City

Popular Test Prep

ACT Test Prep in Seattle, MCAT Test Prep in Phoenix, GRE Test Prep in Denver, ACT Test Prep in Atlanta, ACT Test Prep in Houston, SAT Test Prep in New York City, ACT Test Prep in New York City, GRE Test Prep in Phoenix, SSAT Test Prep in Chicago, SAT Test Prep in Boston

DMCA Complaint

If you believe that content available by means of the Website (as defined in our Terms of Service) infringes one or more of your copyrights, please notify us by providing a written notice (“Infringement Notice”) containing the information described below to the designated agent listed below. If Varsity Tutors takes action in response to an Infringement Notice, it will make a good faith attempt to contact the party that made such content available by means of the most recent email address, if any, provided by such party to Varsity Tutors.

Your Infringement Notice may be forwarded to the party that made the content available or to third parties such as ChillingEffects.org.

Please be advised that you will be liable for damages (including costs and attorneys’ fees) if you materially misrepresent that a product or activity is infringing your copyrights. Thus, if you are not sure content located on or linked-to by the Website infringes your copyright, you should consider first contacting an attorney.

Please follow these steps to file a notice:

You must include the following:

A physical or electronic signature of the copyright owner or a person authorized to act on their behalf; An identification of the copyright claimed to have been infringed; A description of the nature and exact location of the content that you claim to infringe your copyright, in \ sufficient detail to permit Varsity Tutors to find and positively identify that content; for example we require a link to the specific question (not just the name of the question) that contains the content and a description of which specific portion of the question – an image, a link, the text, etc – your complaint refers to; Your name, address, telephone number and email address; and A statement by you: (a) that you believe in good faith that the use of the content that you claim to infringe your copyright is not authorized by law, or by the copyright owner or such owner’s agent; (b) that all of the information contained in your Infringement Notice is accurate, and (c) under penalty of perjury, that you are either the copyright owner or a person authorized to act on their behalf.

Send your complaint to our designated agent at:

Charles Cohn Varsity Tutors LLC
101 S. Hanley Rd, Suite 300
St. Louis, MO 63105

Or fill out the form below:

Do not fill in this field

Contact Information

* Full legal name

Company name

* Phone number

* Email address

Address

* Address1

Address2

* City

* State

* Zipcode

* Country

Complaint Details

* URL of copyrighted work (where your original material is located)

* Please describe the copyrighted work so that it may be easily identified

I am the owner, or an agent authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.

I have a good faith belief that the use of the material in the manner complained of is not authorized by the copyright owner, its agent, or the law.

This notification is accurate.

I acknowledge that there may be adverse legal consequences for making false or bad faith allegations of copyright infringement by using this process.

* Signature (your digital signature is legally binding)

HIGH SCHOOL

GRADUATE SCHOOL

K-8

Search 50+ Tests

math tutoring

science tutoring

foreign languages

elementary tutoring

other

Search 350+ Subjects

ISEE Upper Level Math : Radius

Study concepts, example questions & explanations for ISEE Upper Level Math

All ISEE Upper Level Math Resources

Example Questions

Example Question #1 : Radius

Example Question #1 : Radius

Example Question #2 : Radius

Example Question #2 : How To Find The Length Of A Radius

Example Question #3 : How To Find The Length Of A Radius

Example Question #2 : How To Find The Length Of A Radius

Example Question #1 : Area Of A Circle

Example Question #122 : Area

Example Question #3 : Radius

Example Question #4 : Know And Use The Formulas For The Area And Circumference Of A Circle: Ccss.Math.Content.7.G.B.4

All ISEE Upper Level Math Resources

Report an issue with this question

DMCA Complaint

Contact Information

Address

Complaint Details

Email address:
Your name:
Feedback: