ABCD is quadrilateral in which . If , if , then find .
Step Drawing the diagram:
Given :
ABCD is quadrilateral in which and .
Draw a line through C parallel to DA intersecting AB produced at E.
Step Finding :
We have, and
(By construction).
Therefore, AECD is a parallelogram.
Therefore, (Opposite sides of a parallelogram)
(Given)
Therefore,
(Angles opposite to equal sides are equal)
Also, (Interior angles on the same side of transversal is supplemenatry)
And (Linear pair axiom)
Hence,