Answer:
The following points are on the line
- (x,y) = (2,120)
- (x,y) = (3,180)
- (x,y) = (4,240)
There are other points on the line, but I'm focusing on the points where the three filled in circles are shown. I'm ignoring (0,0) because that point won't be useful for the next section below.
Pick any of the three points and divide y over x
- y/x = 120/2 = 60
- y/x = 180/3 = 60
- y/x = 240/3 = 60
Whatever point you choose, you'll get the same ratio. The constant of proportionality is 60.
In the context of this problem, the 60 refers to the speed of the car.
The car travels 60 miles in 1 hour, or at a speed of 60 mph.
