Area Contractor

This lesson gives students the opportunity to explore surface area in the same way that a contractor might when providing an estimate to a potential customer. Once the customer accepts the estimate, a more detailed measurement is taken and a quote prepared. In this lesson, students use estimation to determine the surface area of the walls and floor of their classroom. They check the reasonableness of their estimates, and then measure the classroom for accuracy. In this two part lesson, an estimation is done first and then an actual measure to check for accuracy.

Weblink address (URL): 
Area Contractor

Standards & Objectives

Learning objectives: 

Learning Objectives:

Students will:

  • Estimate area of walls and floor using reference items or points in a room.
  • Estimate area of windows, doors, and any obstructions that cannot be moved or that the customer does not want moved.
  • Estimate net surface area of walls and floor by subtracting the area of any obstructions from the appropriate wall or floor gross estimate.
  • Calculate actual gross surface area of walls and floor using a tape measure, within ±1 inch tolerance (or as determined by you).
  • Determine net surface area of walls and floor through actual measurement of surface area less any obstructions such as chalkboards, cabinets, windows, doors, etc., within a tolerance determined by you.
Essential and guiding questions: 

Questions for Students:

  • If you were the customer, would you want your contractor to overstate or understate the estimate? Which would be better if you were the contractor? Why? 
  • What are some situations in which an estimate is usually sufficient?  
  • Describe a situation where precision is critical.

Lesson Variations

Blooms taxonomy level: 
Understanding
Extension suggestions: 

Extensions:

  • Groups can compete for accuracy of estimates without being under. As well, as part of the opener for Part 2, let students know that bonus points will be awarded for the most accurate measurement. Note: In order to offer this extension, you will need accurate measurements of the classroom before starting this lesson. Your school’s building engineer may have that information available.
  • Add additional elements to the estimation task, such as the ceiling and any trim.
  • Invite a guest speaker to talk about the process of providing estimates.
  • Consider asking your building engineer to come in and present the estimate request to your students.

Helpful Hints

Materials:

  • Measuring tape (1 per group; tapes 25 feet or longer provide the best accuracy)  
  • Chart paper and markers  
  • Area Contractor Activity Sheet  

References

Contributors: 
Roxann Johnson
Originator: 
Ayers Institute for Learning & Innovation