In Fig. 7.140, ∠AB=90∘ and BD⊥AC. If AB = 5.7 cm, BD = 3.8 cm and CD=5.4 cm, find BC.
In ABC and
ADB
ABC =
ADB (right angle)
BAD =
BAC (common angle)
180 - (ABC +
BAC ) = 180 - (
ADB +
BAD )
DBA =
BCA (proved)
Hence both the triangles are similar.
(Corresponding sides of similar triangles)
BC = 1.2 cm