Question

16.
a) Prove that the median of an isoceles triangle divides it into two congruent
triangles.
(Or)
b) In the adjacent figure AD is the angle
bisector of /_BAC. and if
B
/_BED = /_CED
then show that ∆ ABC is an isoceles triangle.​

Answer 1

Step-by-step explanation:

In △ABC, we have

AB=AC

⇒∠C=∠B ∣ Since angles opposite to equal sides are equal

⇒

2

1

∠B=

2

1

∠C

⇒∠OBC=∠OCB

⇒∠ABO=∠ACO …(1)

⇒OB=OC ∣ Since sides opp. to equal ∠s are equal …(2)

(ii) Now, in △ABO and △ACO, we have

AB=AC ∣ Given

∠ABO=∠ACO ∣ From (1)

OB=OC ∣ From (2)

∴ By SAS criterion of congruence, we have

△ABO≅△ACO

⇒∠BAO=∠CAO ∣ Since corresponding parts of congruent triangles are equal

⇒ AO bisects ∠A