Question 377787
here's the strategy
you can fill in all the little details for a "formal" proof


let M be the point of intersection of BC and the bisector


BM equals MC ___ definition of bisector (given)


angle BMA equals (congruent) angle CMA ___ right angles formed by the perpendicular are equal
(perpendicular is given)


AM equals AM (itself) ___ reflection identity


so triangle BMA equals (congruent) triangle CMA ___ SAS


AB equals (congruent) AC ___ Corresponding Parts of Congruent Triangles are Congruent