Answer:
base is 5
Step-by-step explanation:
the reason is 5 is because the formula of the parallelogram is base times height
since they gave us the area which is 20 and we have the height we have to do the opposite of multiplying which is divide so we divide 20 with 4 which gave is 5 as our base and to check 4 times 5 is 20 so its correct
