Area of Rectangles — Let's Practice!

Area of Rectangles — Let's Practice! exercise

• Identify the formula for finding the area of a rectangle.

  Hints

  Part of the formula is to multiply the longer length of the rectangle.
  For example: In this rectangle, 8 x (other measurement) = area.

  Part of the formula is to multiply the shorter length of the rectangle.
  For example: In this rectangle, 2 x (other measurement) = area.

  Solution

  • To find the area of a rectangle, multiply the length of the rectangle, times the width. Your answer should be squared. For example, square inches, square feet, square miles.
  • This rectangle has an area of 16 units squared because 8 (length) x 2 (width) is 16.

• Find the length and width of the various rectangles.

  Hints

  Count the squares on the longest side to find the length.

  Count the squares on the shortest side to find the width.

  Solution

  • Rectangle 1

  Length = 8 units.
  Width = 3 units.

  • Rectangle 2

  Length = 4 units.
  Width = 2 units.

  • Rectangle 3

  Length = 6 units.
  Width = 3 units.

  • Rectangle 4

  Length = 8 units.
  Width = 1 unit.

• Find the area of the various rectangles.

  Hints

  To find the area of a rectangle, multiply the length of the rectangle, times the width. On this rectangle, the length is 8 units, and the width is 2, so multiply 8 x 2 to find the area.

  To find the area of a rectangle, you can multiply the sides, or you can also count the total number of squares.

  Solution

  • Rectangle 1

  6 x 3 = 18 square units.

  • Rectangle 2

  1 x 8 = 8 square units.

  • Rectangle 3

  3 x 8 = 24 square units.

  • Rectangle 4

  2 x 4 = 8 square units.

• Find the length, width, and area of the rectangles.

  Hints

  Count the squares on the longest side to find the length, then multiply this measurement by the width.

  Count the squares on the shortest side to find the width, then multiply this measurement by the length.

  To find the area of a rectangle, you can multiply the sides, or you can also count the total number of squares.

  Solution

  • Square 1

  Length = 3, width = 3
  3 x 3 = 9 units squared.

  • Rectangle 2

  Length = 8, width = 3
  8 x 3 = 24 units squared.

  • Rectangle 3

  Length = 5, width = 4
  5 x 4 = 20 units squared.

  • Rectangle 4

  Length = 8, width = 2
  8 x 2 = 16 units squared.

• Find the area of the rectangle.

  Hints

  Count the squares on the longest side to find the length.
  Use this measurement as part of the formula.

  Count the squares on the shortest side to find the width.
  Use this measurement as part of the formula.

  To find the area of a rectangle, you can multiply the sides, or you can also count the total number of squares.

  Solution

  • The longest side is 5 units. This is the length.
  • The shortest side is 4 units. This is the width.
  • Length x width = area squared.
  • 5 x 4 = 20 units squared.

• Find the area, length, or width of the various rectangles.

  Hints

  Count the squares on the longest side to find the length, then multiply by the width to find the area.
  In this rectangle, the length is 8 units, the width is 2 units.
  8 x 2 = 16.
  The area is 16 units squared.

  To find the length, count the longer side or divide the area by the width.
  This rectangle has an area of 16 units squared.
  This rectangle has a width of 2 units.
  16 ÷ 2 = 8.
  The length is 8 units.

  To find the width, count the shorter side or divide the area by the length.
  This rectangle has an area of 16 units squared.
  This rectangle has a length of 8 units.
  16 ÷ 8 = 2.
  The length is 2 units.

  Solution

  • Rectangle 1

  8 x 12 = 96.
  The area is 96 square units.

  • Rectangle 2

  45 ÷ 5 = 9.
  The length is 9 units.

  • Rectangle 3

  36 ÷ 9 = 4.
  The width is 4 units.

  • Rectangle 4

  7 x 8 = 56 square units.
  The area is 56 square units.