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Question
The radius of a circle is 8 cm. calculate the length of a tangent draw to this circle from a point at a distance of 10 cm from its centre.
Solution
OP = 10 cm; radius OT = 8 cm
∵ OT ⊥ PT
In right ΔOTP,
OP2 = OT2 + PT2
102 = 82 + PT2
PT2 = 100 – 64
PT2 = 36
PT = 6
Length of tangent = 6 cm.
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