Geometry

Lesson 9

Math

Unit 6

7th Grade

Lesson 9 of 21

Objective


Solve real-world and mathematical problems using the relationship between the area of a circle and its radius.

Common Core Standards


Core Standards

  • 7.G.B.4 — Know the formulas for the area and circumference of a circle and use them to solve problems; give an informal derivation of the relationship between the circumference and area of a circle.

Criteria for Success


  1. Know the formula that relates the area and radius of a circle: $${{A=\pi r^2}}$$.
  2. Use the formula $${{A=\pi r^2}}$$ to solve problems.

Tips for Teachers


Lessons 8 and 9 focus on the relationship between a circle’s area and its radius. In Lesson 9, students will solve real-world and mathematical problems involving area. Students will solve more problems involving all measurements of circles in Lessons 10 and 11.

Fishtank Plus

Unlock features to optimize your prep time, plan engaging lessons, and monitor student progress.

Anchor Problems

25-30 minutes


Problem 1

Suzanne is making a circular table of out a square piece of wood. The diameter of the circle she is cutting is 6 feet. How much waste will she have for this project? Express your answer to the nearest square foot.

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

Student Response

Upgrade to Fishtank Plus to view Sample Response.

References

EngageNY Mathematics Grade 7 Mathematics > Module 3 > Topic C > Lesson 17Example 3

Grade 7 Mathematics > Module 3 > Topic C > Lesson 17 of the New York State Common Core Mathematics Curriculum from EngageNY and Great Minds. © 2015 Great Minds. Licensed by EngageNY of the New York State Education Department under the CC BY-NC-SA 3.0 US license. Accessed Dec. 2, 2016, 5:15 p.m..

Modified by Fishtank Learning, Inc.

Problem 2

Recall the image below from Lesson 7, composed of a square and two semi-circles. Find the area of the figure. 

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

Student Response

Upgrade to Fishtank Plus to view Sample Response.

Problem 3

A 12 ft. rope is attached to the wall of a garage. A dog’s collar is attached to the end of the rope to allow him to safely stay outside. What is the area of the space the dog has outside?

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

Student Response

Upgrade to Fishtank Plus to view Sample Response.

Problem Set

15-20 minutes


Give your students more opportunities to practice the skills in this lesson with a downloadable problem set aligned to the daily objective.

Target Task

5-10 minutes


A circular platter fits exactly into a box. The base of the box is a square with side lengths 24 cm. 

What is the area of the circular platter? 

Student Response

Upgrade to Fishtank Plus to view Sample Response.

Additional Practice


The following resources include problems and activities aligned to the objective of the lesson that can be used for additional practice or to create your own problem set.

  • Include problems with composite shapes including simple quadrilaterals, triangle, and circles or semi-circles.
  • Include problems where students determine the percent increase in area from one circle to another; for example, a medium pizza has a diameter of 14 inches and a large pizza has a diameter of 16 inches. By what percent is the area of the large pizza greater than the medium pizza?

Next

Solve problems involving area and circumference of two-dimensional figures (Part 1).

Lesson 10
icon/arrow/right/large

Lesson Map

A7CB09C2-D12F-4F55-80DB-37298FF0A765

Topic A: Angle Relationships

Topic B: Circles

Topic C: Building Polygons and Triangles

Topic D: Solid Figures

Request a Demo

See all of the features of Fishtank in action and begin the conversation about adoption.

Learn more about Fishtank Learning School Adoption.

Contact Information

School Information

What courses are you interested in?

ELA

Math

Are you interested in onboarding professional learning for your teachers and instructional leaders?

Yes

No

Any other information you would like to provide about your school?

We Handle Materials So You Can Focus on Students

We Handle Materials So You Can Focus on Students

We've got you covered with rigorous, relevant, and adaptable math lesson plans for free