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In δAbc, Ad is Perpendicular to Bc. Prove That: Ab2 + Cd2 = Ac2 + Bd2

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Question

In ΔABC, AD is perpendicular to BC. Prove that: AB2 + CD2 = AC2 + BD2

Sum
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Solution


Since triangle ABD and ACD are right triangle right-angled at D,
AB2 = AD2 + BD   ....(i)
AC2 = AD2 + CD2   ....(ii)
Subtracting (ii) and (i), we get
AB2 - AC2 = BD2 - CD2
⇒ AB2 + CD2 = AC2 + BD2.

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Chapter 12: Pythagoras Theorem - Exercise 17.1

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Frank Mathematics Part 1 [English] Class 9 ICSE
Chapter 12 Pythagoras Theorem
Exercise 17.1 | Q 12

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