How to tell which side is the hypotenuse adjacent and opposite?

The tiles below are pieces of a normal ecg tracing representing a little less than two heartbeats at a resting rate of 80 bpm. arrange the tiles in their correct order. rank from first to last. do not overlap any tiles.

Write a similarity statement for the similar triangles. afgh ~ a

What multiplys to be 1 but adds up to be 4