If the bisector of the vertical angle of a triangle bisects the base, prove that the triangle is isosceles.
Given,
In ΔPQR,
PS bisects ∠QPR and QS = SR
To prove:
PQ = PR
In ΔPQS and ΔPRS
QS = SR [Given]
∠QPS = ∠RPS [Given]
PS = PS [Common]
ΔPQS is congruent to ΔPRS [S.A.S]
⸫ PQ = PR [C.P.C.T.C]
Hence Proved.