Answer
$36$ square centimeters
Work Step by Step
The area $A$ of a rectangle is given by the formula $A=lw$ where $l$ is the length and $w$ is the width.
Substitute the given values into the formula to obtain:
$A=(9\text{ cm.})(4\text{ cm.})$
$A=36\text{ cm.}^2$
Hence, the area of the rectangle is $36$ square centimeters.
