Can you help me in my math please?

Question

If <1 is supplementary to <2 and <3 ~= <1, prove AD II BC.

this is the picture for the question.
http://aycu14.webshots.com/image/23453/2003993084943664995_rs.jpg

Answer 1

The sum of the interior angles of a 4-sided figure are

(4-2) x 180 = 360

If <1 and <2 are suppl. and <1 ~ <3,
then <3 and and <2 and
This proves the quadrilateral must be a parallelogram.
By definition of a parallelogram, opposite sides are parallel.
So AD || BC.

Answer 2

as 1+2=180 then they are interior angles as 1=3 alternate then AD II BC