If a rectangle has side lengths $a$ units and $b$ units, the area is $a \boldcdot b$ square units. For example, if we have a rectangle with $\frac12$-inch side lengths, its area is $\frac12 \boldcdot \frac12$ or $\frac14$ square inches.
This means that if we know the area and one side length of a rectangle, we can divide to find the other side length.
If one side length of a rectangle is $10\frac12$ in and its area is $89\frac14$ in2, we can write this equation to show their relationship: $$\frac12 \boldcdot {?} =89\frac14$$
Then, we can find the other side length, in inches, using division: $$89\frac14 \div 10\frac12 = {?}$$