Answer:
Part 4) AA Similarity Postulate
Part 5)
The congruent angles are
m<ACB=m<CED , m<ABC=m<CDE, m<BAC=m<DCE
The proportional segments are

Step-by-step explanation:
Part 4) we know that
If BC is parallel to DE
then
Triangles ABC and CDE are similar by AA Similarity Postulate ( the three interior angles are congruent)
so
m<ACB=m<CED ------> by corresponding angles
m<ABC=m<CDE -----> both angles measure is 90 degrees
m<BAC=m<DCE -----> the sum of the interior angles of a triangle must be equal to 180 degrees
If two figures are similar, then the ratio of its corresponding sides is equal
so

substitute the values

Find DE


In the triangle ABC
Applying Pythagoras Theorem
Find AC




Find CE


