The area of the parallelogram is equal to the base times height. The formula to use is A = b*h. The height and base are always perpendicular to one another.
The base is some unknown variable b. Multiply the base by the height 15 to get 15*b which is equal to the area 135
Therefore, 15*b = 135
Divide both sides by 15 and we isolate b
15b = 135
15b/15 = 135/15
b = 9
So the base is 9
Check:
area = base*height = 9*15 = 135
so the answer is confirmed
side note: we never use the value 17 at all. It is likely put in there as a distraction.
