Q. 63.6( 38 Votes )

AB, CD, PQ are perpendicular to BD. AB = x, CD = y and PQ = z prove that 1/x + 1/y = 1/z

Answer :

Given, in Δ BCD, PQ || CD


And in Δ ABD, PQ||AB


Need to prove that

From eq(1) and eq(2) we have

1- [FROM EQ(1)]

1 = PQ()


Since, from the question we know that AB = X CD = Y and PQ = z

Substituting those values in eq(3) we get

Hence proved

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