So ∠ABC=∠DEF

And because ∠A=∠D BC=EF.

Similarity can be obtained from corner edges.

A 1(0，2)

B 1(3，2)

C 1(3，0)

19。

Two angles of PC arc ∠PDC=∠ 1

Because ∠1= ∠ c.

Then < PDC = < c

So parallel