## Loading...

# Measuring to find Perimeter and Area

Lesson 10 of 14

## Objective: SWBAT measure dimensions of triangles, rectangles and circles in order to find their areas and perimeters.

#### Activating Prior Knowledge

*15 min*

**Where We've Been:** Students have just had a refresher on the concepts of area and perimeter. They have also practiced applying the formulas for perimeter, area, and circumference to non-scale drawings with dimensions given.

**Where We're Going:** In the near future, we'll be using coordinate geometry to find perimeters and areas in the coordinate plane. But first we'll do some good old fashioned hands-on measuring with a ruler to find real areas.

So for this lesson I start by having students complete the APK_Measure Area and Perimeter student resource. I give students five minutes to complete the handout, and then I spend 5 minutes going over the correct answers.

#### Resources

*expand content*

#### Hands on Activity

*30 min*

For this section of the exercise, students receive a copy of the Measuring Area and Perimeter student resource.

Several things are intentionally left to student discretion. For example, students will need to decide how precise to be with their measurements and how best to organize and notate their work.

My job during this activity is to circulate the room looking for misconceivers and directionphobics. As usual, my approach is to ask open ended questions that force these students to confront their errors and move past them. The biggest issues tend to be lack of precision with measurement, incorrect or missing units, not using the correct height for triangles, and quitting on the hexagon figure (not seeing it as a composition of triangles and rectangles).

#### Resources

*expand content*

Now that students know how to measure a figure that already exist to determine its area and perimeter, the next level of cognition is for students to create their own figures that have specified areas and perimeters.

So giving them that chance is the Creating Figures to Specifications student resource.

I run this activity as a guided practice.

Starting with the first figure, I tell the class that they'll have x number of minutes to complete their drawings. At the end of the time, I ask for volunteers (or later on non-volunteers) to come to the document camera and argue for their figure meeting the specifications. Then I ask if anyone would like to challenge the validity of the student's claims. If applicable, I would also ask if anyone wants to show how they did it another way that is also correct.

#### Resources

*expand content*

- UNIT 1: Community Building, Norms, and Expectations
- UNIT 2: Geometry Foundations
- UNIT 3: Developing Logic and Proof
- UNIT 4: Defining Transformations
- UNIT 5: Quadrilaterals
- UNIT 6: Similarity
- UNIT 7: Right Triangles and Trigonometry
- UNIT 8: Circles
- UNIT 9: Analytic Geometry
- UNIT 10: Areas of Plane Figures
- UNIT 11: Measurement and Dimension
- UNIT 12: Unit Circle Trigonmetry
- UNIT 13: Extras

- LESSON 1: Origins of the Geometric Universe
- LESSON 2: Line Segments
- LESSON 3: Distances in the Coordinate Plane
- LESSON 4: Exploring Midpoint Quadrilaterals
- LESSON 5: Investigating Points, Segments, Rays, and Lines
- LESSON 6: Formative Assessment Day 1
- LESSON 7: Introducing Angles
- LESSON 8: Angle Measurements
- LESSON 9: Basic Constructions
- LESSON 10: Measuring to find Perimeter and Area
- LESSON 11: Finding Perimeter and Area in the Coordinate Plane
- LESSON 12: Geometry Foundations Summative Assessment Practice Day 1 of 2
- LESSON 13: Geometry Foundations Summative Assessment Practice Day 2 of 2
- LESSON 14: Introduction to Transformations