The area of a rectangle is given by $A=l\times w$A=l×w, where $l$l is the length and $w$w is the width. Both length and width must be of the same units when performing the multiplication to find the area.
What would the unit for area be if the length and width are in millimeters?
Apply the relationships between units in the metric system, including the units for measuring different attributes and derived measures
Apply measurement in solving problems