In figure, if ∠BAC =90° and AD⊥BC. Then, (a) BD.CD = BC² (b) AB.AC = BC² (c) BD.CD=AD² (d) AB.AC =AD²
In figure, if ∠BAC =90° and AD⊥BC. Then, (a) BD.CD = BC² (b) AB.AC = BC² (c) BD.CD=AD² (d) AB.AC =AD²

Solution:

c) BD.CD=AD²

Explanation:

From triangles ADB and ADC,

Now according to the question, we have,

∠ADB = ∠ADC = 90° (Since AD ⊥ BC)

∠DBA = ∠DAC [As each angle = 90°- ∠C]

Using AAA criterion for similarity,

∆ADC∼ ∆ADB

AD/CD = BD/AD

AD2 = BD.CD