2Area of a Circle Discovery For Learning to Happen:Pay close attention to this lesson.Listen to my instructions to discover the area of a circle formula.
3Area of a Circle Discovery You are going to get a white half sheet.Label the circumference, diameter and radius on your circle.
4Area of a Circle Discovery CircumferenceDiameterRadiusCarefully cut out the circle on the black line.
5Area of a Circle Discovery Cut out the circle on the bolded lines.Cut along the diameter to cut the circle in half.You should have 2 halves.
6Area of a Circle Discovery Start from the diameter and cut the 4 pieces.DO NOT CUT IT TO THE EDGE!Open the semicircles and bend them out so they look like 4 connected triangles.
7Area of a Circle Discovery Fit the 4 triangles together so that as one is facing up, the other is facing down.Tape these pieces together on your blue study guide handout.Make sure your words on facing up!radiusCircumference
8Area of a Circle Discovery Answer the following questions.What does your new figure look like?Parallelogram2a. Draw your answer here. Label base & height2b. How do you find the area of a parallelogram?Base x Heightheightbase
9Area of a Circle Discovery 3. Draw your area of a circle figure below. In knowing that you need to find the base and height of your new figure to calculate the area, what is the height of your new figure? Label your picture.4. What is the bottom base of your new figure? Label your picture above. Hint: Half of the circumference.Height = radiuspi x radius
10Area of a Circle Discovery If you know the base and height of your new figure can you find the area? Take your base and multiply it by your height. Show your work!6. Simplify your formula.7. Write out how you find the area of a circle.Pi times radius squared.
11Area of a Circle Discovery Here is what we just did:We labeled everything.Area = base timesthe height.rrradiusCircumference isthe distancearound the circle.We cut our circlein half making twopieces.
12Area of a Circle Discovery Watch what happens when we use a circle with 16 triangles instead of using a circle with 8 triangles.rrNotice that with more triangles the figure begins to really resemble a parallelogram. Area of a parallelogram is base times height.
13Area of a Circle Discovery Take out a calculator to try to solve the following problems on area of a circle.
14Area of a Circle Discovery 6 in.Find the area of the circle.
15Area of a Circle Discovery 11 m.Find the area of the circle.
16Find the area of the circle. Area of a Circle DiscoveryWhat is the radius if the diameter is 10 ft?10 ft.Find the area of the circle.
17Take out your study guide! Area of a Circle DiscoveryThat's all Folks!The End!Take out your study guide!That’s all folks
21Use this as a master to give to students for the interactive discovery of a circle along with a copy of the worksheet.Student materials for interactive discovery of a circle: Copy of circle pictured above, copy of area worksheet in this folder, scissors & tape.
22Area of a Circle Area of a Circle Follow the teacher directions and cut the circle out.Area of a CircleFollow the teacher directions and cut the circle out.
23TEACHER NOTE: Give each student a copy of this page TEACHER NOTE: Give each student a copy of this page. The master copy is in the folder as a pdf.