But how many feet is he running each time?
Parallel lines have the same slope.
So the graph of [ y = 3x + any number ] is parallel
to the graph of [ y = 3x - 10 ] .
The area of the red piece of paper is A= 4(2*4)= 4*8= 32 in^2.
The area of the blue piece of paper is A= 3*7=21 in^2. You subtract 21 from 32 and the difference is 11. So 11in^2 is visible.
