Consider the diagram and proof by contradiction. Given: ABC with ZB ZC
Prove: ABAC
It is given that ZB ~ 2C. Assume AB and AC are not
congruent. If AB > AC, then m2C>m ZB by
If AC > AB, then mZB>m2C for the same reason.
However, using the given statement and the definition of
congruency, we know that m ZB = m 2C. Therefore, AB
= AC and AB AC.
A
What is the missing reason in the proof?
O converse of the triangle parts relationship theorem
O substitution
O definition of congruency
converse of the isosceles triangle theorerything
B
с