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In a Triangle Abc Right Angled at C, P and Q Are Points of Sides Ca and Cb Respectively, Which Divide These Sides the Ratio 2 : 1. Prove That: 9bp2 = 9bc2 + 4ac2 - Mathematics

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प्रश्न

In a triangle ABC right angled at C, P and Q are points of sides CA and CB respectively, which divide these sides the ratio 2 : 1.
Prove that: 9BP2 = 9BC2 + 4AC2

योग
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उत्तर


P divides AC in the ratio 2 : 1

So C.P. = `(2)/(3) "AC"` .......(i)

Q divides BC in the ratio 2 : 1

QC = `(2)/(3)"BC"` ......(ii)

Applying Pythagoras theorem in right triangle BCP, we have
BP2 = BC2 + CP2

⇒ BP2 = `"BC"^2 + (4)/(9)"AC"^2`   ...(Using (i))

⇒ 9BP2 = 9BC2 + 4AC2.

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अध्याय 17: Pythagoras Theorem - Exercise 17.1

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फ्रैंक Mathematics [English] Class 9 ICSE
अध्याय 17 Pythagoras Theorem
Exercise 17.1 | Q 20.2

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