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PE02234_.WMF (15424 bytes)AREA OF THE LAWN PROJECT
By Kirk Brower
University of Idaho
GRADES 7-9

 

ITV Series: MATH TALK #112 Data Analysis: How do I compute it?

Overview
One of the necessary elements of algebra is area. Students should be able to understand how basic algebra problems are solved. This lesson will introduce a brief series of practical problem solving skills related to area. To give students a practical example of how and when area computations may be necessary students will calculate the area of a yard, while viewing the video, and determine the price that should be charged for mowing in order to make a profit.  Students should be familiar with basic area problems as well as cost efficiencies.  These lessons are designed to assess students' abilities to compute area calculations in meaningful and practical methods.   Great lessons to make math come alive for junior high students!


Learning Objectives

Students should be able to:

  • Compute simple area calculations in real-life situations.
  • Determine simple wage computations.
  • Use critical thinking skills.
  • Demonstrate their ability to use writing in order to express mathematical thoughts and processes.

Materials

  • Pencils and writing materials
  • A notebook or graphing paper
  • A 30 meter measuring tape
  • Recording materials
  • Calculator (optional)
  • Word processing accessibility for finalized reports
  • Drawing program such as mini-cad or Auto-cad (not necessary but desired)

Previewing Activity

Review the idea of area. Ask students to demonstrate how area is calculated. Have some basic sample problems to illustrate on the chalkboard or overhead projector.

Ask students when they think computing the area of something may be useful. Have a classroom discussion to brainstorm some ideas. Lists may include concrete workers, carpet layers, fence builders, etc.

Focus for Viewing

To give students responsibility for viewing have students listen for and record how much the caller is paid.  There are several points during the video for students to participate in discussions.  Students will need to have a pencil and paper during viewing.


Viewing Activities

BEGIN the video at the beginning of the episode starting with the cartoon introduction of Buster the Parrot and Maria Lopez at the news desk..

PAUSE The Video after Aussie, the caller, tells how much she gets paid to mow the lawn. Ask students if they mow their lawn at home. How much do they get paid? Is their lawn large? Is it worth it?

RESUME the Video and PAUSE the Video after the episode of "Daddy Knows Best" returns to the news station with Buster the Parrot and Maria, immediately following her statement, "further viewing is required." Have students respond to the following oral questions:

  • Do you think it will be worth 1 cent per square meter?
  • In order to receive about 10 dollars for the job, would the lawn need to be very large? How can you determine this?
  • If the lawn were 500 square meters, estimate how much you think the son would earn.
  • How large do you think a 500 square meter lawn would be?
  • About how much money do you think you could make mowing your own lawn at this price?

RESUME Video and PAUSE after Daddy Amberson finds out his machine does not work. Ask students how they might determine the area. Do they know? Ask for volunteers to illustrate their methods on the chalkboard or overhead projector. Make sure only about 5-7 minutes is allowed for this demonstration.

 RESUME Video and PAUSE after Daddy Amberson says, "I don't know how to find the area of a big "U" shape." Ask students how they might solve for the area of the yard. Give them an overhead illustration or diagram on the chalkboard. Allow time for discussion of ideas to take place.

RESUME Video and PAUSE after the caller says, "I'm into the environment for the big bucks." Ask students if they could divide the lawn into different ways to increase the area. Have a volunteer demonstrate how you could or could not.

RESUME Video and PAUSE after the prosecutor says, "I rest my case." Ask the students the following questions:

  • Who would you rule in favor of?
  • Which do you think is bigger? Smaller?
  • Do you think they are the same size?
  • What do you estimate the two sizes to be?
  • How could you know the exact size of each?

RESUME the Video and STOP the Video after Maria says, "See you next time on Math Talk."

Post Viewing Activities

Have students do a prewriting activity in which they estimate what it costs to have the school's lawn mowed. How long do they think it would take them? What do you think is a fair price? How much would you charge? What are some factors that may affect the price of mowing the lawn?

Divide students into groups of three. Assign them different portions of the school property, and have them measure lengths and widths of various sections of lawn with their 30 meter tape measures.

Have each group create a diagram of their portion of lawn (using Auto-cad or Mini-cad if available) while computing the area.

Have each group determine the cost to mow the lawn if they pay someone I cent per square meter.

Have students combine their data to determine the total area of the school's lawn and the cost to mow it. Using the computer software available (or sketching), draw a diagram of the entire schoolyard labeling measurements and areas. 

Incorporate a problem solving activity to determine the cost of fuel to mow the entire lawn.

Finalize the project by having students interview a custodial worker to find out how much is paid to mow the school's grass. Have them put together a written formal assessment (using a word processing program) of how much it costs to mow the school lawn, how much time it takes, and how much money is spent on gas, determining whether or not the school is spending their money wisely.

Extensions

  • Have students find the cost of the Mona Lisa and determine what it is worth per square inch.
  • Have students find what percent of their home state's area is water, forest, farms, etc.
  • Have the students research the foundations of area. What mathematicians used area formulas a lot in their work?
  • Have students choose a career that interests them and see how area is used in the profession. Have students interview a representative or worker from the profession to inquire about these calculations.
  • Talk to various golf course managers to determine the area of their courses, and what it costs to take care of them. Compare three or four courses to see which is saving the most money.
  • For additional lesson plans and ideas relating to this topic and many others try TeacherSource!   You will find activities, lesson plans, teacher guides and links to other great educational web sites!  Search the database by keyword, grade level or subject area! 
  • Mathline and Scienceline are also great resources for teachers seeking teaching tips, lesson plans, assessment methods, professional development, and much more!  Look for a localized version of Mathline and Scienceline on IdahoPTV next year!

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