Geometryhard · Past Paper
In the figure, O is the center. AB is a chord and PT is the tangent at T. If PT = 12 cm and the distance of P from the center is 13 cm, find the radius.
A5 cm
B7 cm
C10 cm
D25 cm
✓ Correct Answer: A — 5 cm
By Pythagoras theorem in triangle OTP, r^2 + 12^2 = 13^2 => r = 5 cm.
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