Geometrymedium · Past Paper

Two concentric circles have radii 5 cm and 3 cm. Find the length of the chord of the larger circle which touches the smaller circle.

A4 cm
B6 cm
C8 cm
D10 cm

✓ Correct Answer: C8 cm

Using Pythagoras: Half chord length = sqrt(5^2 - 3^2) = sqrt(16) = 4 cm. Full chord = 8 cm.

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