Lesson: Perimeters

Lesson: Perimeters of Common Shapes/ My Day’s Perimeter

§111.5. Mathematics, Grade 3, Adopted 2012

(7) Geometry and measurement. The student applies mathematical process standards to select appropriate units, strategies, and tools to solve problems involving customary and metric measurement. The student is expected to:

(B) determine the perimeter of a polygon or a missing length when given perimeter and remaining side lengths in problems;

Three Part Objective: After practicing finding the perimeter on various shapes, students will be able to find the perimeter of the four different shapes on page 709 and the shape in problem 13 on page 710.

​

Materials:
• 25rulers
• 25piecesofyarn
• 25ShapeWorksheets
• 25workbooks
• MyDay’sPerimeterPowerPoint Gain Attention:

I will ask the students if they know what schoolIamfrom.ThenIwilltellthemthe story about how I take the bus around campus to get around and if not I walk. Then I will show them the path the bus takes to go from where I live, to the gym, to the library, study at the union, and back home. This path makes a rectangle, I will ask if they notice anything about this path. Then I will ask them, if it was a day that I had to walk, how far will I walk that day. If any of them have answer I will take them,

then I will ask how they did or how we could figure out the answer. One way, I will suggest if no one figures it out, is to add up all the sides of the rectangle.

​

Inform the Learner of the Objective:

Today we will be learning about perimeters of common shapes. The perimeter is the measurement of all the sides of a shape put together.

​

Stimulate Recall of Prior Knowledge:

We will look at the different common shapes and different qualities about them (i.e. squares have four sides with equal length, rectangles have two pairs of sides withequallength,numberofsidesand vertices of various polygons).

Present the Material:

The perimeter is the measurement of all the sides of a shape put together. To find the perimeter of a shape we add the length of each side together. This can be done for all shapes: squares, triangles and more. I will start with the problem on page 707 as an example. If they need more practice with this we can do the problems on page 708 aswell.WhileIampresentingIwilltake periodic checks with the class to see if they are all with me by having them do a three-finger check (1- lost, 2-get it a little, 3- understand completely). We will do the guided practice on page 709 together, and I will guide them through the steps, asking them what the next step is each time.

Present the Material:

The perimeter is the measurement of all the sides of a shape put together. To find the perimeter of a shape we add the length of each side together. This can be done for all shapes: squares, triangles and more. I will start with the problem on page 707 as an example. If they need more practice with this we can do the problems on page 708 as well. While I am presenting I will take periodic checks with the class to see if they are all with me by having them do a three- finger check (1- lost, 2-get it a little, 3- understand completely). We will do the guided practice on page 709 together, and I will guide them through the steps, asking them what the next step is each time.

​

Provide Guidance to the Learner:

We will do the guided practice on page 709 together, and I will guide them through the steps, asking them what the next step is each time.

​

Elicit Performance:

Iwillhavethestudentsuseastringandruler to measure the perimeter of different shapes. The will use the string to trace the shape, then measure the used yarn to the They will also do problems 1-4 on page 709 and 12-13 on page 710 in their workbooks.

Give Feedback:

•Wonderful work!
•Great idea on how to solve the problem!

•I love how ____ is working quietly on their problems.

•Great idea on how to use perimeters!

Assess Performance:

Students will do problems 1-4 on page 709 and 12-13 on page 710 in their workbooks after completing the string measurement practice.

Enhance Retention and Transfer:

After the class finishes their workbook problems, I will ask them what was interesting about what they learned today. I will take several student responses. Then, I will ask the students how they might use this outside of the classroom. Hopefully the students will remember the perimeter of my travel route as one, otherwise we will discuss their examples and I will eventually remind them about my day’s perimeter. However, if they cannot think of any ways to use perimeter outside of class, I will suggest if they were building a fence and needed to buy material or if they were missing a side.