Subjects

Careers

Open the App

Subjects

Easy Circle Math: How to Draw and Understand Circle Graphs

Open

21

1

user profile picture

Diallo

2/13/2023

Algebra 2

8.3 Equations of circle

Easy Circle Math: How to Draw and Understand Circle Graphs

The equation of a circle and its tangent lines are fundamental concepts in analytic geometry. This guide explores circle equations, graphing techniques, and tangent line calculations.

Circle equations and graphing:

  • Standard form of a circle equation: (x-h)² + (y-k)² = r²
  • h and k represent the center coordinates, r is the radius
  • Equation of a circle examples and graphing methods are discussed
  • Tools like WolframAlpha and Desmos can be used for visualization

Tangent lines to circles:

  • Tangent line touches the circle at exactly one point
  • Calculating tangent line equations involves slope and point of tangency
  • Examples demonstrate how to find tangent line equations

Key applications:

  • Graphing circles and understanding their properties
  • Solving real-world problems involving circular objects
  • Analyzing relationships between circles and lines

This guide provides a comprehensive overview of circle equations, graphing techniques, and tangent line calculations, suitable for students learning analytic geometry.

...

2/13/2023

653

Formula:
(x-h)² + (y_k)²²= ²
Chapter 8.3
1) Graph 2 you
2
xz 6
Example 1
x² + y² = 36
Center 10;0)
2-X +36
(0,0)
(2;-5)
x² + y ² z r²²
6
(=)

View

Tangent Lines to Circles

This page focuses on finding the equation of a tangent line to a circle, a key concept in analytic geometry. The main example presented is finding the tangent line to the circle x² + y² = 13 at the point 3,2-3, 2.

Definition: A tangent line to a circle is a line that touches the circle at exactly one point, called the point of tangency.

The process of finding the tangent line equation involves several steps:

  1. Identify the point of tangency 3,2-3, 2 and the circle equation x² + y² = 13.
  2. Calculate the slope of the radius at the point of tangency, which is perpendicular to the tangent line.
  3. Use the perpendicular slope to find the slope of the tangent line.
  4. Apply the point-slope form of a line equation to derive the tangent line equation.

Example: For the circle x² + y² = 13 and point of tangency 3,2-3, 2, the tangent line equation is derived as y = 3/43/4x + 13/4.

The page includes a diagram illustrating the circle, the point of tangency, and the tangent line, which helps visualize the geometric relationship.

Highlight: Understanding how to find the equation of tangent to a circle from an external point is crucial for solving more advanced problems in geometry and calculus.

This example demonstrates the practical application of circle equations and line equations in solving geometric problems. It showcases how analytical methods can be used to describe geometric relationships precisely.

Can't find what you're looking for? Explore other subjects.

Knowunity is the # 1 ranked education app in five European countries

Knowunity was a featured story by Apple and has consistently topped the app store charts within the education category in Germany, Italy, Poland, Switzerland and United Kingdom. Join Knowunity today and help millions of students around the world.

Ranked #1 Education App

Download in

Google Play

Download in

App Store

Knowunity is the # 1 ranked education app in five European countries

4.9+

Average App Rating

21 M

Students use Knowunity

#1

In Education App Charts in 17 Countries

950 K+

Students uploaded study notes

Still not sure? Look at what your fellow peers are saying...

iOS User

I love this app so much [...] I recommend Knowunity to everyone!!! I went from a C to an A with it :D

Stefan S, iOS User

The application is very simple and well designed. So far I have found what I was looking for :D

SuSSan, iOS User

Love this App ❤️, I use it basically all the time whenever I'm studying

 

Algebra 2

653

Jun 27, 2025

2 pages

Easy Circle Math: How to Draw and Understand Circle Graphs

The equation of a circle and its tangent lines are fundamental concepts in analytic geometry. This guide explores circle equations, graphing techniques, and tangent line calculations.

Circle equations and graphing:

  • Standard form of a circle equation: (x-h)² + (y-k)² =... Show more

Formula:
(x-h)² + (y_k)²²= ²
Chapter 8.3
1) Graph 2 you
2
xz 6
Example 1
x² + y² = 36
Center 10;0)
2-X +36
(0,0)
(2;-5)
x² + y ² z r²²
6
(=)

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Tangent Lines to Circles

This page focuses on finding the equation of a tangent line to a circle, a key concept in analytic geometry. The main example presented is finding the tangent line to the circle x² + y² = 13 at the point 3,2-3, 2.

Definition: A tangent line to a circle is a line that touches the circle at exactly one point, called the point of tangency.

The process of finding the tangent line equation involves several steps:

  1. Identify the point of tangency 3,2-3, 2 and the circle equation x² + y² = 13.
  2. Calculate the slope of the radius at the point of tangency, which is perpendicular to the tangent line.
  3. Use the perpendicular slope to find the slope of the tangent line.
  4. Apply the point-slope form of a line equation to derive the tangent line equation.

Example: For the circle x² + y² = 13 and point of tangency 3,2-3, 2, the tangent line equation is derived as y = 3/43/4x + 13/4.

The page includes a diagram illustrating the circle, the point of tangency, and the tangent line, which helps visualize the geometric relationship.

Highlight: Understanding how to find the equation of tangent to a circle from an external point is crucial for solving more advanced problems in geometry and calculus.

This example demonstrates the practical application of circle equations and line equations in solving geometric problems. It showcases how analytical methods can be used to describe geometric relationships precisely.

Formula:
(x-h)² + (y_k)²²= ²
Chapter 8.3
1) Graph 2 you
2
xz 6
Example 1
x² + y² = 36
Center 10;0)
2-X +36
(0,0)
(2;-5)
x² + y ² z r²²
6
(=)

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Circle Equations and Graphing

This page introduces the fundamental concepts of circle equations and graphing techniques. The standard form of a circle graph equation is presented as xhx-h² + yky-k² = r², where h,kh,k represents the center coordinates and r is the radius.

Definition: The equation xhx-h² + yky-k² = r² is the standard form of a circle equation, where h,kh,k is the center and r is the radius.

Two examples are provided to illustrate how to work with circle equations:

Example: For the equation x² + y² = 36, the center is at 0,00,0 and the radius is 6.

Example: To find the equation of a circle with center at the origin 0,00,0 and passing through the point 2,52,-5, we use the distance formula to calculate the radius: r = √(02(0-2² + 0+50+5²) = √29. Thus, the equation is x² + y² = 29.

The page also mentions tools that can be used for visualizing circles:

Highlight: Tools like WolframAlpha and Desmos can be used as a circle graph equation calculator or to graph a circle on Desmos.

These examples demonstrate how to derive circle equations from given information and how to interpret the components of the equation. Understanding these concepts is crucial for solving more complex problems involving circles in analytic geometry.

We thought you’d never ask...

What is the Knowunity AI companion?

Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.

Where can I download the Knowunity app?

You can download the app in the Google Play Store and in the Apple App Store.

Is Knowunity really free of charge?

You have the choice, we offer a 100% secure payment via PayPal or an Amazon gift card. There is no limit to how much you can earn.

Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.9/5

App Store

4.8/5

Google Play

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️

Thomas R

iOS user

Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades

Brad T

Android user

Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend

Aubrey

iOS user

Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀

Marco B

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!

Paul T

iOS user

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️

Thomas R

iOS user

Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades

Brad T

Android user

Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend

Aubrey

iOS user

Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀

Marco B

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!

Paul T

iOS user