The area of a rectangular field is 8811 m2. if the width of the field is 89m, what is the length?

Length = 99 because ...

since you multiply to get the area, in order to find the missing term of an area (in this case its length), you do the opposite of what you started with ... so if you multiplied to get the area, you need to divide to get the missing side ...

so 8811 divided by 89 = 99

99 x 89 = 8811