Given :
N lies on a side of the square ABCD,AM and LC are perpendicular to DN,
To Find : prove that ∠ADN= ∠LCD.
Solution
Let say
∠ADN= α
∠LCD = β
∠ADN + ∠CDN = 90° ( ∠D = angle of square )
=> α + ∠CDN = 90°
∠CDN = ∠CDL
=> α + ∠CDL = 90°
in ΔCDL
∠CDL + ∠LCD + ∠DLC = 180° ( sum of angles of triangle )
∠DLC = 90° as LC is perpendicular to DN
=> ∠CDL + β + 90° = 180°
=> ∠CDL + β = 90°
α + ∠CDL = 90°
∠CDL + β = 90°
Equating both
α + ∠CDL = ∠CDL + β
=> α = β
=> ∠ADN= ∠LCD
QED
Hence Proved
In the diagram ,N lies on a side of the square ABCD,AM and LC are perpendicular to DN,prove that ADN=LCD.
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