Answer:
Let x represent the number of minutes.
Lets y represents the number of beats.
Now consider the graph, when the time is equal to 1 min, the total beats are 60. We can say that this point can be taken in a coordinate plane as (1,60).
Similarly, when time is equal to 2 mins, total beats are 120, and when time is equal to 3 mins, total beats are equal to 180 mins. So the these points on the coordinate plane can be represented as (2,120) and (3,180)
Plot all the three points, and draw a line which joins them and extend the line. The line shows the proportionality relation between both values