A rectangle is a foursided polygon with four right angles, whose opposite sides are parallel and are equal.
A rectangle is a particular sort of parallelogram, but can't say that all parallelograms would be rectangles, because a rectangle is a shape where opposites sides are parallel and all the corners are 90 degree angles. Some parallelograms would be rectangles, but not all.
Area of a rectangle
The area of a rectangle is the product of its width and length.
What is the area?
Find the base and height of the rectangle.
base: 
14 km 
height: 
24 km 
Use these numbers in the formula.
Area 
= base × height 

= 14 × 24 

= 336 
Now find the units. The lengths are measured in kilometers, so the area is measured in square kilometers.
The area is 
336 
square kilometers. 
What is the area when b=3, and h=3?