What is this fraction as a decimal?

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.

What is the measure of the smallest angle in the diagram? 15 29 32 45

Write an equation for the function that includes the points (1,4/5) and (2,2/3)