Geometry prostulate and theorem help. please 3 questions.?

Question

can someone please help me with these questions? thank you in advance. number 14 got cut off but it says "what prostulate or theorem justifies the statement pqr~stu?"

link

http://i127.photobucket.com/albums/p153/nanipics1/emamgeo001.jpg

Answer 1

14.  Two triangles are similar if at least two corresponding angles are equal.

15.  If two corresponding sides of two triangles are in proportion, and their included angles are equal, the triangles are similar.

16.  If three sides of two triangles are in proportion, the triangles are similar.