Question

Write a two column proof for the following conjecture. Statements and reasons

Answer 1

Information is given(reasons are in the parenthesis) 

Angle A and angle B are supplementary. Angle B and Angle C are supplementary  (given)


DC is parallel to AB (consecutive interior angles are supplementary )
BC is parallel to AD (consecutive interior angles are supplementary)

ABCD is a parallelogram (definition of parallelogram, has to pairs of parallel sides)