3rd Grade Math Lesson Plan: Area of a Rectangle, Square, or Triangle

Lesson Objective: Students will be able to find the area of a rectangle, square or triangle.

Lesson Opening

1. Open with a few analogies that demonstrate the difference between area and perimeter, for instance asking them if you consider a pizza crust and the whole pizza, which is the perimeter and which is the area.

Guided Practice

1. A quick review of perimeter from yesterday where I pretend that I am two years old and that I do not understand any of it. Warning: sometimes this tactic gets them riled up.

1. An explanation of a square inch, using props and showing how tiling a floor can show you how many square inches there are. Make sure that every answer they give is in square inches. If they don't give an answer in square inches, ask them "Five what? Five monkeys?" etc. to remind them.

1. Show the shortcut that works by multiplying. Show how this is the same as the tiling effect with the square inches. If there is time, and there won't be, show them how to find the area of a triangle.

Independent Practice

1. Have them measure the same items that they did for perimeter using area.

Closing

1. Asking the question, "What kinds of jobs require a knowledge of area?"