Two concentric circles are of radii 15 cm and 9 cm. What is the length of the chord of the larger circle which is tangent to the smaller circle (in cm)?
Show answer & explanation
Correct answer: C
Explanation
Correct Answer is option 3 i.e. 24 cm
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Concept |
Understanding |
Application |
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Tangent is always perpendicular to radius of a circle.
The perpendicular for centre of a circle divides the chord in 2 equal parts. |
Radius 15 cm and 9 cm. The tangent PQ to smaller circle, is a chord of bigger circle. Hence, PT = TQ = PQ/2
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In triangle TOQ: TQ = √(152-92) = 12 cm
Hence, PQ = 12 × 2 = 24 cm |
