Prove that the lengths of tangents drawn from an external point to a circle are equal. Using the above, prove that PP’ = QQ’ in the figure.

P'A=P'Q         tangents from external point  ....(1)

also,

AP=AQ          tangents from external point....(2)

subtracting(1)and (2),

AP-AP'=AQ-AQ'

Therefore, PP'=QQ'

 

  • 6
What are you looking for?