Intersection Of Two Circles
Overview
Two circles can miss each other, touch at a single point, or cross at two. Finding where they meet looks daunting, because each equation has squared terms, but a single subtraction sweeps the squares away and leaves a straight line: the common chord. From there the problem becomes the familiar line-meets-circle.
In this lesson you will subtract one circle equation from the other to find the line through the intersection points, substitute back into a circle to find the points themselves, and use the number of solutions to decide whether the circles intersect, touch or miss.
Objectives
- Solve problems involving the intersection of two circles, including finding points of intersection and the equation of a common chord, and determining whether two circles intersect, touch or do not intersect.
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Lesson Evaluation
Congratulations on completing the lesson on Intersection Of Two Circles. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Subtracting one circle equation from another eliminates which terms? A. the constants B. the x^2 and y^2 terms C. the x terms only D. nothing Answer: B
- The line obtained by subtracting two circle equations is called the: A. tangent B. common chord C. diameter D. normal Answer: B
- For x^2 + y^2 = 25 and (x - 8)^2 + y^2 = 41, the common chord is: A. x = 3 B. y = 3 C. x = 4 D. y = 4 Answer: A
- The circles x^2 + y^2 = 25 and (x - 8)^2 + y^2 = 41 meet at: A. (3, 4) and (3, -4) B. (4, 3) and (-4, 3) C. (5, 0) only D. they do not meet Answer: A
- If substituting the common chord gives y^2 = 0, the circles: A. intersect at two points B. touch at one point C. miss D. are identical Answer: B
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