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Question
In the given figure, QR is parallel to AB and DR is parallel to AB and DR is parallel to QB.
Prove that: PQ2 = PD × PA.
Solution
Given, QR is parallel to AB.
Using Basic proportionality theorem,
`=> (PQ)/(PA) = (PR)/(PB)` ...(1)
Also, DR is parallel to QB.
Using Basic proportionality theorem,
`=> (PD)/(PQ) = (PR)/(PB)` ...(2)
From (1) and (2), we get,
`(PQ)/(PA) = (PD)/(PQ)`
PQ2 = PD × PA
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