Circles Craft

How can a stack of paper plates make reviewing circles more fun? I gave each student a paper plate and displayed these definitions on the board:

• center - middle of circle
• radius - line segment from center to side
• diameter - line segment from side to side through center
• cord - line segment from side to side not through center
• circumference - distance around

When they finished labeling, we used the other side to display measurement of the paper plate. (The plate was just over nine inches; we rounded this number to make it easier for fourth graders to handle.) From the diameter, they were able to calculate the radius, and they were excited because I "let them" use formulas, calculators, and the almighty pi to compute area and circumference. I displayed the formulas, and away they went!

• d = 2r
• C = π d  or  C = 2 π r
• A = π r 2

Enjoy!