Question

Given: AB parallel to DC, AB congruent to BC
Prove: a. AD congruent to CB
b. AD parallel to BC

Answer 1

<1=<4 alternate angels
<2=<3 alternate angels
<2=<4 Isosceles triangle
thus
<1=<2=<3=<4
then <C=<A

Answer 2

<1=<4 alternate angels
<2=<3 alternate angels
AC common
so by ASA
triangle ADC congruent triangle ABC
thus
AD=BC

Answer 3

<D=<B