Two concentric circles are of radii $13\text{ cm}$ and $5\text{ cm}$. Find the length of the chord of the larger circle which touches the smaller circle.
Step-by-Step Solution
Key Concept: Half chord $= \sqrt{13^2 - 5^2} = \sqrt{169 - 25} = \sqrt{144} = 12\text{ cm}$. Full chord $= 2 \times 12 = 24\text{ cm}$.
Half chord length $= \sqrt{169 - 25} = \sqrt{144} = 12\text{ cm}$. [1.0 Mark]
Length of chord $= 2 \times 12 = 24\text{ cm}$. [1.0 Mark]
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🎯 Official CBSE Marking Scheme:
Finding half chord $= 12\text{ cm}$: 1.0 Mark
Evaluating total chord length $= 24\text{ cm}$: 1.0 Mark
Correct Answer: