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# Circumference and Area of Circles

Lesson 2 of 18

## Objective: Students will be able to apply the formulas for area and circumference of circles to solve real world and mathematical problems.

## Big Idea: Ever play a song back in your head over and over? You will be singing about area and circumference all day after this lesson!

*60 minutes*

#### Launch

*10 min*

**Opener: **As students enter the room, they will immediately begin working on the opener. The opener is a mixture of previously learned questions, and students should work individually, and then as table groups to discuss the methods for solving the questions. During this time I will assist those students who were absent the previous day, and any other students needing help. After approximately 5 minutes, I will call on students to go to the board and solve the opener questions. As with all openers, I will take volunteers to go to the board – the volunteer is expected to explain their reasoning, and other students are expected to follow along with the work and ask questions/make suggestions as necessary. By having a student explain their reasoning while others listen and provide feedback, **mathematical practice 3** – construct viable arguments and critique the reasoning of others – becomes a natural part of class. Instructional Strategy - Process for openers

**Learning Target: **After completion of the opener, I will address the day’s learning targets to the students. In today’s lesson, the intended targets are, “I can solve real world and mathematical problems involving area of a circle.” Students will jot the learning targets down in their agendas (our version of a student planner, there is a place to write the learning target for every day).

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#### Explore

*40 min*

https://www.flocabulary.com/circles/ This song is a catchy way for students to remember the area and circumference of circles. I will play the song while I get the notes passed out.

Area and Circumference Notes: After the fun song, I will move into some formal notes on area, and then a few whole class practice problems. I will work a few problems out with the kids, and then set the off to complete the remaining problems on their own. I am curious to see how kids do with the bicycle question - I have found in the past that many students struggle to realize this is a circumference question.

Instructional Strategy - How do table challenges work?: With their table groups and a white board, students will respond to 7 area and circumference problems. This is a good way for me to assess who gets it and who doesn't :) Additionally, their are word problems included so students will have to determine whether they are solving for area or circumference.

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#### Summarize + Homework

*10 min*

**Class Discussion: **After the table challenge, I will wrap up the lesson by asking “Who can give us a real world example of when we would apply the area of a circle problem?” (**MP 4**) taking volunteers for responses. The purpose of this activity will be to make sure that students understand when it would be appropriate to calculate area, versus circumference. Normally, lots of hands go up for this question – which is always a good sign!

**Homework: **After discussion of the question, I will pass out homework, and allow students the last few minutes of class to look it over and ask any questions needed for clarification. Philosophy on Homework

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Always super great stuff, Heather. I use your materials A LOT! Christina Ferguson, Roswell, NM :)

| 2 years ago | Reply*Responding to Laura Rigby*

I use her notes a lot as well. The answers are in Smart Notebook files. I don't have a SmartBoard so I can't use the file, but you can download it and upload it and view it on http://express.smarttech.com/#.

| 2 years ago | Reply

Heather,

I use a lot of your lessons, or parts of them -- thank you! I would really love it if you could provide an answer key as well. Sometimes, especially with notes, it takes me a bit to figure out what you would write in the fill in the blanks.

| 2 years ago | Reply

Great ideas and I love the table challenge! Thanks.

I guess I am missing something, however... the 7 questions they will answer in their table groups... did you supply them?

thanks!

Adrienne

| 2 years ago | Reply

Thank you Heather. I haven't had a chance to give you feedback. I've used a lot of your lessons. They are easy for me to follow and great for the students.

| 2 years ago | Reply

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- UNIT 1: Introduction to Mathematical Practices
- UNIT 2: Proportional Reasoning
- UNIT 3: Percents
- UNIT 4: Operations with Rational Numbers
- UNIT 5: Expressions
- UNIT 6: Equations
- UNIT 7: Geometric Figures
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- LESSON 1: Relationship Between Circumference and Diameter - What is pi?
- LESSON 2: Circumference and Area of Circles
- LESSON 3: Area of Irregular Figures - How do you break up a figure?
- LESSON 4: Working Backwards with Formulas - How do I undo a formula?
- LESSON 5: 2D Figures - Review Time!
- LESSON 6: Composite Figures and Circles Test
- LESSON 7: Intro to 3D Figures and Cross-Sections - What shape do you see?
- LESSON 8: Volume of Prisms - How are base area and volume of a prism related?
- LESSON 9: Volume of Square Pyramids - What is the relationship between and prism and pyramid?
- LESSON 10: Volume of Prisms and Pyramids Fluency Practice
- LESSON 11: Surface Area of a Rectangular Prism - What shapes do you see?
- LESSON 12: Surface Area of a Triangular Prism - What shape is the base?
- LESSON 13: Surface Area of Triangular and Rectangular Prisms Fluency Practice
- LESSON 14: Surface Area of a Square Pyramid - What shapes are the faces?
- LESSON 15: Volume and Surface Area of Prisms and Pyramids Fluency Practice
- LESSON 16: Volume and Surface Area Review
- LESSON 17: 2D and 3D Volume and Area Test
- LESSON 18: Surface Area and Volume Centers -5 Days of Enrichment and/or Remediation