Answer
$A=4,320\text{ in}^2$
Work Step by Step
The formula for the area of a rectangle is $A=bh$. In order to use this formula, however, we must have the same units for the base and the height. Since there are $36$ inches in a yard, we multiply the number of yards of the base by $36$ to get the number of inches of the base: $$4\text{ yd}\times\frac{36\text{ in}}{1\text{ yd}}=144\text{ in}$$We now plug in the values for the base and the height into the formula and simplify: $$A=30\text{ in}(144\text{ in})=4,320\text{ in}^2$$
