In an isosceles triangle ABC, with AB=AC, the bisectors of angle B and angle c intersect
each other at O. Join A to 0. Show that OB=OC.
Answers
Answer:
Step-by-step explanation:
In ΔABC, AB = AC
⇒ ∠B = ∠C [Angles opposite to equal sides are equal]
Also OA and OB are bisectors of angles B and C.
⇒ ∠OBC = ∠OCB
∴ OB = OC [Sides opposite to equal angles are equal]
Now consider, Δ’s AOB and AOC
OA = OA (Common side)
AB = AC (Given)
OB = OC (Proved)
ΔAOB ≅ ΔAOC [By SSS congruence criterion]
⇒ ∠OAB = ∠OAC
That is OA is bisector ∠A.
Step-by-step explanation:
Solution:-
Given:-
AB = AC and
the bisectors of B and C intersect each other at O
(i) Since ABC is an isosceles with AB = AC,
B = C
½ B = ½ C
⇒ OBC = OCB (Angle bisectors)
∴ OB = OC (Side opposite to the equal angles are equal.)
(ii) In ΔAOB and ΔAOC,
AB = AC (Given in the question)
AO = AO (Common arm)
OB = OC (As Proved Already)
So, ΔAOB ΔAOC by SSS congruence condition.
BAO = CAO (by CPCT)
Thus, AO bisects A.