Answer:
{5 ft, 18 ft}, {1 ft, 90 ft}, {9 ft, 10 ft}
Explanation:
Represent the length and width by L and W respectively.
Then one requirement may be expressed as L > W.
The other requirement is L * W = 90 ft^2.
Let's temporarily replace W in this equation with L:
L^2 = 90 ft^2, so that L must be the positive square root of 90 ft^2:
L = √(90 ft^2) ≈ 9.5
Since L must be greater than W, we can write L > 9.5 ft. The nearest integer L would be 10, in which case the nearest integer W would be 9, which means that the area of the stage would be 90 ft^2 (as required).
{9 ft, 10 ft} are possible whole number measurements for L and W. Here W < L, as required, and L and W are both integers.
{5 ft, 18 ft} is another possible set of measurements.
So is {1 ft, 90 ft}.