First one
take the ratio of the long sides of each triangle 66/55 = 1.2
take the ratio of the NEXT longest legs 60/50 = 1.2 Good so far
IF the ratio of the third legs is the same (1.2), the triangles are similar
55/45 = 1.2222 Uh-Oh...... the triangle are NOT similar (Close though)
Second one
can you tell me for what the little red arrows stand ?