Could one of this site's math Wizards please help me with this. The teacher wants me to make a 2 column proof that proves this and I am kind of stuck. The topic for this week is triangle inequailities.

OkNietzsche Apr 14, 2019

#1**+1 **

(1) AB = AC Given

(2) Angle ABC = Angle ACB In a triangle, angles opposite equal sides are also equal

(3) Measure of Angle ACB = Exterior Angle Theorem

Measure of Angle CAD +

Measure of Angle ADC

(4) Measure of Angle ACB > Consequence of (3)

Measure of Angle ADC

(5) Measure of Angle ABC > Substitution

Measure of Angle ADC

(6) Measure Angle B > By (5)

Measure Angle D

CPhill Apr 14, 2019

#2**+1 **

Thank you for this but I have one question. How is your step 3 the Alternate Exterior Angles Theorem? I do not understand how you got that and I was wondering if you could elaborate.

OkNietzsche
Apr 14, 2019