Teacher Lesson Plan
Approximate length of time: about 30 minutes
Outline of the activity: Students will measure length of a circle’s diameter for 3 different size hula hoops or other circular objects. Record data. Calculate each circle’s circumference. Calculate area of each circle. Determine the relationship between radius and area.
Student materials: data sheet, string, calculator
Assessment/evaluation piece: Students will present findings on various hoop sizes    cumulative data presentation.
Teaser: Have the studentsbrainstorm times when you have had to calculate accurate proportions?
Challenge:
http://www.mathforum.org/library/drmath/view/58039.html
Student Worksheets
Name __________________________ Hula Hoop Activity #1
Comparing a circle’s circumference with its area and a circle’s radius with its area.
Materials:
Procedure:
Hula 
Diameter 
Circumference 
Area 
1 

2 

3 
Answer the following questions:
Radius 
Area = pr2 
14 

10 
Using your calculations from the 14inch and 10inch pizza, what is the relationship between the radius and area?
Name ________________________ Quiz
relationships in circles
1) A stepping stone has a radius of 5 inches. What is the relationship between that stepping stone and a stepping stone that has twice the radius (which means a radius of 10 inches)?
National Science Standards
Materials List
Student materials: