Math - 2018-19

3.8 - Perimeter and Area

The student will 

a)  estimate and measure the distance around a polygon in order to determine its perimeter using U.S. Customary and metric units; and

b)  estimate and count the number of square units needed to cover a given surface in order to determine its area. 

Adopted: 2016


  • So that I can measure my back yard to find out how much fencing is needed to close it in

  • So that I can determine how much paint is needed to paint my bedroom


  • A polygon is a closed plane figure composed of at least three line segments that do not cross.  A plane figure is any closed, two-dimensional shape.
  • Perimeter is the path or distance around any plane figure.
  • Area is the number of iterations of a two-dimensional unit needed to cover a surface.  The two-dimensional unit is usually a square, but it could also be another shape such as a rectangle or an equilateral triangle. 
  • The unit of measure used to find the perimeter or area is stated along with the numerical value when expressing the perimeter or area of a figure (e.g., the perimeter of the book cover is 38 inches and the area of the book cover is 90 square inches).
  • Opportunities to explore the concepts of perimeter and area should involve hands-on experiences (e.g., placing toothpicks (units) around a polygon and counting the number of toothpicks to determine its perimeter and filling or covering a polygon with tiles (square units) and counting the tiles to determine its area). 


The student will use problem solving, mathematical communication, mathematical reasoning, connections, and representations to

  • Estimate and use U.S. Customary and metric units to measure the distance around a polygon with no more than six sides to determine the perimeter. (a)
  • Determine the area of a given surface by estimating and then counting the number of square units needed to cover the surface. (b)


Updated: Aug 22, 2018