You can cut off the piece sticking out and "attach" it to the other side to make a complete rectangle. From there, multiply 4.5 * 24. You should end up with 108 cm².
Average rate of change is the same as finding slope between a line on a non- linear function. Using the ordered pairs (5,10) and (8,1) (10-1)/(5-8) = 9/-2 = -9/2
