Math, asked by nisha5779, 1 year ago

plz solve this problem plzzzzzzzzZ

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Answered by nitkumkumar
0

Answer:

This can be proved by applying similarity of triangles .

Step-by-step explanation:

In ΔOAF and ΔOBD

∠O = ∠O          (common)

∠OAE = ∠OBD        (given 90° as perpendicular)

=>  ΔOAF ~ ΔOBD        [BY AA criteria]

=>  OA/OB = FA/DB       (sides are proportional of similar triangles)  .........(1)

Also, in ΔFAC and ΔEBC

∠FAC  =  ∠EBC       (given perpendicular)

∠FCA = ∠BCE          (vertically opposite angles)

=>   ΔFAC ~ ΔEBC       [AA  criteria]

Thus, FA/EB = AC/BC     (sides are proportional of similar triangles)  

But ,  EB = DB                   (given)

=>    FA/DB = AC/BC             ...................(2)

From equation(1) and (2)

OA/OB =  AC/BC  

=> OA/OB =  (OC - OA)/(OB - OC)

=>  OA * (OB - OC) = OB * (OC - OA)

=> OA * OB - OA * OC  =  OB * OC- OB * OA

=>  OA * OB + OB * OA  =  OB * OC + OA * OC

=>  2(OA * OB)  = (OA + OB) * OC

Now, Dividing both sides by OA * OB * OC

=>  2(OA * OB)/[OA * OB * OC] = [(OA + OB) * OC]/[OA * OB * OC]

=>  2/OC  =  [(OA + OB)]/[OA * OB]

=>  2/OC = OA/[OA * OB] + OB/[OA * OB]

=>   2/OC =  1/OB + 1/OA

=>   1/OB + 1/OA = 2/OC

Hence proved .

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