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.

Answer 1

 
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.