In a right triangle ABC with right angle at B, BD is a perpendicular, dropped onto the hypotenuse. If AC = 2AB, what is the area of Δ ABD? given, area of Δ ABC = 5 sq units.
A
0.5 sq. unit
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
1 sq. unit
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
1.25 sq. unit
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
5 sq. unit
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is C 1.25 sq. unit
Given,ABAC=12andAr(ΔABC)=5sq.unitsConsiderΔABDandΔABC:∠BAD=∠BAC−−−−[commomangle]∠BDA=∠ABC−−−−[90∘]By AA similarity criterion,ΔABD∼ΔABCHence,Ar(ΔABD)Ar(ΔABC)=(ABAC)2=(12)2=14i.e.,Ar(ΔABD)×4=Ar(ΔACB)⇒Ar(ΔABD)=54=1.25sq.unitsHencetheareaofΔABDis1.25sq.units