Question

in fig c,AD ⏊ BC ,∠ABE=110°,∠ACB=30°,find ∠DAB,∠DACand∠CAF
​

Answer 1

Answer:

Step-by-step explanation:To prove : AB×EF=AD×EC

⇒

EC

AB

​

=

EF

AD

​

Proof :

AB=AC (∵ ABC is isosceles)

∴∠B=∠C (angles opposite to equal sides are equal) - (1)

In ΔABD and ΔECF

∠ABD=∠ECF (from (1))

∠ADB=∠EFC (Both are 90

∘

)

Using AA similarity

ΔADB∼ΔECF

⇒

EC

AB

​

=

EF

AD

​

⇒AB×EF=AD×EC

∴ Hence proved.