the manager of a music store examined his CD sales by category for the past few months the results are shown in the table if he plans to order 250 new CDs how many of them should be easy to dance​

PART A
Since the graph described will form a straight line, the concept of similar triangles can be used when comparing the slopes on AB and AC. We just imagine a triangle formed by the line segments and their corresponding x and y components. We can notice that their angles don't actually change so we know that the two triangles formed are proportional. This would mean that getting the slope (Δy/Δx) would yield us the same number.

PART B
The initial value of the graph is 60 meters and this represents the initial position of the shark (it is located 60 meters below the ocean surface).

The slope of the graph is  and this represents how fast (speed) the shark can dive. We know this because dividing meters over the number of minutes would give us meters/minute and this is describing the speed.