In a right angled Δ ABC, Right angled at A, AD ⊥ BC.

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In a right angled Δ ABC, Right angled at A, AD ⊥ BC. Then :

1. AD² = BD × CD
2. AD² = AB × AC
3. AD² = BD × AB
4. AD² = CD × AC
5. None of these

Correct Option: A

From above given right angle triangle , we can see that
Since ∠1 + ∠2 = ∠2 + ∠3 (Each 90°)
∴ ∠1 = ∠3 [Each 90°]
Also ∠5 = ∠6 [Each 90°]
∴ ΔADB ∼ ΔCDA [AA Similarity]

AD	=	DB	⇒	AD²	=	BD × CD.
CD		AD