Make sure students understand that a square is also a rectangle, but a special type of rectangle. Does the formula for calculating the perimeter of a rectangle apply to squares? Explain your thinking. The formula does apply, but it is quicker to simply multiply the length of one side by 4 to find the perimeter.Using a ruler, draw and label a right triangle with side lengths of 6 centimeters, 8 centimeters, and 10 centimeters.Using a ruler, draw and label a rectangle with a length of 5 inches and width of 7 inches.What is the perimeter of a triangle with side lengths of 3 feet, 7 feet, and 9 feet? 19 feet.What is the perimeter of a rectangle with length = 10 meters and width = 7 meters? 34 meters.Step 2: Either individually or in pairs, ask students to complete the following problems: Show that a quicker way to calculate perimeter for rectangles is to add the lengths of two adjacent sides and multiply by 2, i.e., 2(l + w). To measure the perimeter of any polygon (a closed figure made up of line segments), you add together the lengths of the sides.

Ask the class to determine the distance around each shape (14 feet for the rectangle, 12 feet for the triangle).Įxplain that perimeter is the distance around a polygon (a closed figure made up of line segments). Then draw a right triangle with a base of 4 feet, a height of 3 feet, and a hypotenuse (the side opposite the right angle) of 5 feet. Step 1: On the board, draw a rectangle labeled with a length of 4 feet and width of 3 feet. Optional: Make class sets of the Setting the Stage With Geometry Take-Home Activity: Poster-Crazy printable and the What’s the Angle? Bonus Worksheet printable for students to complete as part of the Lesson Extensions.Hang a copy of the Setting the Stage With Geometry Classroom Poster printable in your classroom or project it using a computer and projector.Print a copy of the Answer Key: Setting the Stage With Geometry printable for your use.Make class sets of the Setting the Stage With Geometry Worksheet: Geometry Works! The Stage Takes Shape printable and the Setting the Stage With Geometry Reference Sheet: Perimeter, Area, Surface Area, and Volume printable.Optional: What’s the Angle? Bonus Worksheet printable.Optional: Setting the Stage With Geometry Take-Home Activity: Poster-Crazy printable.Setting the Stage With Geometry Classroom Poster printable.Answer Key: Setting the Stage With Geometry printable.Setting the Stage With Geometry Reference Sheet: Perimeter, Area, Surface Area, and Volume printable.Setting the Stage With Geometry Worksheet: Geometry Works! The Stage Takes Shape printable.Understand the formulas that measure the perimeter and area of these basic two-dimensional shapes: rectangles, circles, and triangles.

Perimeter and area worksheets ks3