## Lesson: Circumference and Area

Developing the Concept

Now that students have discovered pi as the relationship between the circumference and diameter of a circle, it is time for them to use pi to find the area of a circle. Posting these formulas around the room can be helpful to students.

**Materials:** one copy of a large circle divided into 8 congruent parts; scissors and rulers for each student

**Preparation:** Draw a large circle on a sheet of paper. Divide it into 8 equal parts as shown below. Make enough copies for the whole class.

**Wrap-Up and Assessment Hints**

Provide students with plenty of practice working with the formulas for circumference and diameter before moving on to area. Have students explain to you what substitutions they make in equations and why. By verbalizing their reasoning, both you and your students will be able to assess their understanding of the topics and proceed at a reasonable rate.