JEE Main 2019MathematicsCircleHardMCQ

JEE Main 2019 — Circle Question with Solution

JEE Main 2019 (09 Jan Shift 1)

Question

Three circles of radii a, b, c, a<b<c touch each other externally. If they have x- axis as a common tangent, then:

Choose an option

Show full solutionCorrect option: A
Correct answer
A1a=1b+1c

Step-by-step explanation

We have,

LM=PN=a+b2-b-a2=2ab

NQ=MS=a+c2-c-a2=2ac

PQ=ST=b+c2-c-b2=2bc

∵ PQ=PN+NQ

⇒2bc=2ab+2ac

⇒1a=1b+1c

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About this question

This is a previous-year question from JEE Main 2019, covering the Circle chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.