GRE Geometry - Rectangles

A rectangle is a four-side figure where opposite sides are equal in length and the four angles are all right angles. The are formula for a rectangle is simply base times height, while the perimeter of a rectangle, or the total distance of its sides, is 2 times the length plus 2 times the width. Rectangles are fairly straight forward, and you should definitely know the area and perimeter formulas by heart. Examples of rectangles, their areas, and perimeters, where A = Area and P = Perimeter:

Notice the following facts:

  • In the third rectangle, the height is x and width is y, and the values for x and y are given, so simple substitution gives the desired area and perimeter values.
  • There is no relationship between the height and width of a rectangle. For example, in the first rectangle, the area is much greater than the perimeter, while in the third rectangle, the perimeter is much greater than the area.
  • A square, the fourth figure, is also a rectangle in which the height and width are equal.