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.
(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
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.