CAT Exam  >  CAT Questions  >  It is known that two circles of radii 3 cm an... Start Learning for Free
It is known that two circles of radii 3 cm and 6 cm have at most 1 common tangent. Let d and D be the minimum and maximum possible distances between their centres. What is the value, in cm, of (D - d)?
    Correct answer is '3'. Can you explain this answer?
    Verified Answer
    It is known that two circles of radii 3 cm and 6 cm have at most 1 com...
    If the two circles have at most 1 common tangent, they can either have no common tangents or one common tangent. They will have no common tangent if one circle is completely within the other with no point of contact, and one common tangent if one circle is inside the other, but there is one point of contact.
    To find d (the minimum distance between centres) we observe that the least distance between centres will occur when the circles are concentric, so d = 0.
    Clearly, the centres will be farthest apart when the circles are tangent to each other (because, in both our cases, we know that one circle is interior to the other).
    Thus, D is equal to the difference in the radii o f the circles = 6 - 3 = 3 cm Further, (D - d) = 3 - 0 = 3 cm Answer: 3
    View all questions of this test
    Most Upvoted Answer
    It is known that two circles of radii 3 cm and 6 cm have at most 1 com...
    Given:
    - Two circles of radii 3 cm and 6 cm

    To find:
    - The minimum and maximum possible distances between their centers

    Solution:
    Step 1: Understand the Problem
    - We need to find the minimum and maximum possible distances between the centers of two circles.
    - The circles have radii of 3 cm and 6 cm.
    - The problem states that the circles have at most 1 common tangent.

    Step 2: Visualize the Circles
    - Let's visualize the two circles and their centers.
    - The circle with a radius of 3 cm will be smaller and the circle with a radius of 6 cm will be larger.

    Step 3: Tangents and Centers
    - In order to find the minimum and maximum distances, we need to consider the position of the common tangent(s) between the circles.
    - Since the circles have at most 1 common tangent, there are two possible cases to consider:
    1. The circles do not intersect.
    2. The circles intersect.

    Step 4: Case 1 - Circles Do Not Intersect
    - In this case, the distance between the centers of the circles is equal to the sum of their radii.
    - The minimum distance (d) will occur when the circles are externally tangent.
    - The distance between the centers will be 3 cm + 6 cm = 9 cm.
    - The maximum distance (D) will occur when the circles are internally tangent.
    - The distance between the centers will be 6 cm - 3 cm = 3 cm.

    Step 5: Case 2 - Circles Intersect
    - In this case, the distance between the centers will be less than the sum of their radii.
    - The minimum distance (d) will occur when the circles are externally tangent.
    - The distance between the centers will be 3 cm + 6 cm = 9 cm.
    - The maximum distance (D) will occur when one circle is completely inside the other.
    - The distance between the centers will be 6 cm - 3 cm = 3 cm.

    Step 6: Comparison and Final Answer
    - Comparing the minimum and maximum distances in both cases:
    - Minimum distance (d) = 9 cm
    - Maximum distance (D) = 3 cm
    - The difference between the maximum and minimum distances is 9 cm - 3 cm = 6 cm.
    - Therefore, the value of (D - d) is 6 cm, which contradicts the given correct answer of 3 cm.
    - There might be an error in the given correct answer, or there could be a misunderstanding in the question or solution approach.
    Free Test
    Community Answer
    It is known that two circles of radii 3 cm and 6 cm have at most 1 com...
    One common tangent means smaller circle is inscribed in side bigger circle touching at one point.now, max and min will be same as 6-3=3 would be distance between there centre
    Attention CAT Students!
    To make sure you are not studying endlessly, EduRev has designed CAT study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in CAT.
    Explore Courses for CAT exam

    Similar CAT Doubts

    It is known that two circles of radii 3 cm and 6 cm have at most 1 common tangent. Let d and D be the minimum and maximum possible distances between their centres. What is the value, in cm, of (D - d)?Correct answer is '3'. Can you explain this answer?
    Question Description
    It is known that two circles of radii 3 cm and 6 cm have at most 1 common tangent. Let d and D be the minimum and maximum possible distances between their centres. What is the value, in cm, of (D - d)?Correct answer is '3'. Can you explain this answer? for CAT 2024 is part of CAT preparation. The Question and answers have been prepared according to the CAT exam syllabus. Information about It is known that two circles of radii 3 cm and 6 cm have at most 1 common tangent. Let d and D be the minimum and maximum possible distances between their centres. What is the value, in cm, of (D - d)?Correct answer is '3'. Can you explain this answer? covers all topics & solutions for CAT 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for It is known that two circles of radii 3 cm and 6 cm have at most 1 common tangent. Let d and D be the minimum and maximum possible distances between their centres. What is the value, in cm, of (D - d)?Correct answer is '3'. Can you explain this answer?.
    Solutions for It is known that two circles of radii 3 cm and 6 cm have at most 1 common tangent. Let d and D be the minimum and maximum possible distances between their centres. What is the value, in cm, of (D - d)?Correct answer is '3'. Can you explain this answer? in English & in Hindi are available as part of our courses for CAT. Download more important topics, notes, lectures and mock test series for CAT Exam by signing up for free.
    Here you can find the meaning of It is known that two circles of radii 3 cm and 6 cm have at most 1 common tangent. Let d and D be the minimum and maximum possible distances between their centres. What is the value, in cm, of (D - d)?Correct answer is '3'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of It is known that two circles of radii 3 cm and 6 cm have at most 1 common tangent. Let d and D be the minimum and maximum possible distances between their centres. What is the value, in cm, of (D - d)?Correct answer is '3'. Can you explain this answer?, a detailed solution for It is known that two circles of radii 3 cm and 6 cm have at most 1 common tangent. Let d and D be the minimum and maximum possible distances between their centres. What is the value, in cm, of (D - d)?Correct answer is '3'. Can you explain this answer? has been provided alongside types of It is known that two circles of radii 3 cm and 6 cm have at most 1 common tangent. Let d and D be the minimum and maximum possible distances between their centres. What is the value, in cm, of (D - d)?Correct answer is '3'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice It is known that two circles of radii 3 cm and 6 cm have at most 1 common tangent. Let d and D be the minimum and maximum possible distances between their centres. What is the value, in cm, of (D - d)?Correct answer is '3'. Can you explain this answer? tests, examples and also practice CAT tests.
    Explore Courses for CAT exam

    Top Courses for CAT

    Explore Courses
    Signup for Free!
    Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
    10M+ students study on EduRev