Area and Perimeter of Rectangles

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Area and Perimeter of Rectangles

• By Liz Rossmeissl

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Who this lesson is for

• This lesson is designed for fourth graders
  learning about area and perimeter of rectangles.
• The slides tell the key components in area and
  perimeter of a rectangle, as well as how to find
  area and perimeter.

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Definitions

• Two of the main components of a rectangle are
  the length and width.
• Length is represented by X, and is the longest
  side of a rectangle.
• Width is represented by Y, and is the shorter
  side of a rectangle.
• There are two lengths and two widths on a
  rectangle. They are parallel to each other, and
  they are each the same measurement (that is, YY
  and XX).

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Area

• Area is determined by the number of 1 x 1
  squares that fit inside the rectangle.
• Square units is a general measurement for area
  because it defines how many squares are in a
  particular shape.
• The equation for area of a rectangle is L x W,
  where L represents length and W represents width.
  So for the rectangle below, the area would be 3 x
  2 6 square units. 3 squares for the length by 2
  squares for the width equals 6 square units.

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Perimeter

• Perimeter is the distance around the rectangle.
  It measures the sum of each side added together.
• The formula for this equation is LLWW, or
  simplified to 2L2W. Rules of algebra allow us to
  simplify the equation further.
• For the rectangle pictured below, the perimeter
  would be 331.51.5 9ft. Unlike area,
  perimeter is not measured in square feet (or
  units). It is just the outside of the shape and
  measures only a distance rather than the inside
  space of the rectangle.

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Resources

• Practice Here is a link that will direct you
  to a game where you can practice calculating the
  area and perimeter of a rectangle. You can choose
  the level you want to play on (easy-super brain),
  and whether you want to find the area, perimeter
  or both. As you calculate the area or perimeter
  correctly, a picture to the left of the game is
  revealed.
• Length Width This is similar to the
  definitions of length and width as described
  earlier in the presentation. It just reiterates
  what was stated.
• Area This is also like the information in the
  power point. It just adds on to what was said
  about the area of a rectangle.
• Perimeter Finally, here is one more link to
  discuss the concept of the perimeter of
  rectangles.