Students Will Be Able to Solve for Circumference When the Area Is Given

• Students will be able to solve for Circumference when the Area is given.
• Determine the radius and diameter when the Area or Circumference are given.
• Compute the Circumference and Area of a Circle.

• Notecards
• Worksheets
• Common Core Achieve Book
• Clickers

• Understanding operations with decimals, the meaning of exponents, solving for circumference and area of a circle, and limited calculator proficiency.

1. “Warm-up” activity called “My Favorite No” – Students learn from mistakes.

1. Pass out index cards or small squares of paper for students to record their answers on, but remind them to not write their names. We want them to be anonymous. Students should take out their Mathematics Formula Sheet & Explanation and use calculators.
2. Draw one circle on the board w/ a radius of 2.5 meters. Students are to solve for the circumference and area of a circle.
3. Students then work out the problem on the notecards (show all work) and provide their answers.
4. Teacher collects cards and makes two piles – “Yes” and “No” (make a note of who has the correct answers as you collect the cards because you can then pair them with a student for additional help). Review the “No” pile and chose a couple to review. Look for notecards w/ the similar mistakes to review.

1. Begin Whole/Small Group Instruction – Using Explicit Instruction Teaching Strategy
2. Ask students to pull out their notebooks or pass out paper for students to take notes.
3. Discuss with students how the ability to solve for circumference and area are necessary for today’s outcomes: “Find the circumference of a circle by using the area.” Students should write this learning target on their papers. The formula for circumference of a circle is related to the formula for the area of a circle. In addition, the circumference and radius can be used to calculate the area and vice versa.
4. Write the following words on the board: exponents, radius, diameter, circumference, area, and pi. Ask students to provide all the information they know and record answers on the board.
5. Modeling/“I do”:
6. Project slide 7/22 from Find the Circumference of a Circle by Using the Area
7. Using a talk aloud, model to students how you solve the problem.
8. Guided Practice/“We do”:
9. Project slide 8/22 from Find the Circumference of a Circle by Using the Area
10. Have students work with you to solve the problem.
11. Application/“You do”:
12. Project slide 18/22 from Find the Circumference of a Circle by Using the Area and have students solve the problems.

1. Before class is over (last 5 min.) – summarize what was learned and discuss the action steps in solving for Circumference when Area is given.
2. Use the area to find the circumference.
3. Use the area formula to find the radius.
4. Use the radius to find the circumference.

1. Have student read pgs. 228 – 231 in Common Core Achieve: Building Essential Test Readiness Skills: Mathematics and complete pgs. 232 – 233.
2. Review answers in class using a student response system (e.g., clickers, white board review, or colored index cards on a ring) to check for 80% accuracy.
3. Collect if needed to record your data and then return to students.

• Students can work in assigned pairs – “Think-Pair-Share” Strategy.
• Teacher will offer extra help to individuals or small group w/ additional word problems.

Ohio ABLE Lesson Plan – Find the Circumference of a Circle When Area is Given1 of 5