Beacon Lesson Plan Library

Pi Day (March 14)

Dan Schmidt
Santa Rosa District Schools


Students will determine the value of PI by measuring the circumference and diameter of circular objects such as soup cans, Oreo cookies, etc..


The student selects and uses strategies to understand words and text, and to make and confirm inferences from what is read, including interpreting diagrams, graphs, and statistical illustrations.

The student locates, gathers, analyzes, and evaluates written information for a variety of purposes, including research projects, real-world tasks, and self-improvement.

Understands that numbers can be represented in a variety of equivalent forms using integers, fractions, decimals, and percents, scientific notation, exponents, radicals, absolute value, or logarithms.

Adds, subtracts, multiplies, and divides real numbers, including square roots and exponents using appropriate methods of computing (mental mathematics, paper-and-pencil, calculator).

Uses concrete and graphic models to derive formulas for finding perimeter, area, surface area, circumference, and volume of two- and three- dimensional shapes including rectangular solids, cylinders, cones and pyramids.

Selects and uses direct (measured) or indirect (not measured) methods of measurement as appropriate.


-PI worksheet (See attached file.)
-Circular objects: Oreo cookie, soup can, and drinking cup
-Ruler (centimeter or inch)
-Marker (mark string)


1. Run-off PI worksheet for each student
2. One centimeter or inch ruler for each group
3. Roll of kite string
4. Marker for each group
5. Calculator for each group
6. Three circular objects to measure for each group


This lesson is similar to one done by the math department at Washington-Marion High School in Lousiana on March 14th of every year.
This activity can be used after discussing how to determine Circumference of circular objects or on March 14 of each year (3-14).

1. Break students in groups of two.

2. One student in each group will get required materials (worksheet, circular objects, ruler, string and marker).
One student will be responsible for measuring objects and the other will be responsible for recording results.

3. Students measure the circumference and diameter of each object using the string and record results on the worksheet. (Note: mark the string and then measure the string against the ruler.)

4. Students will then calculate the value of PI by dividing the diameter into the circumference (C/d) and record answer on the worksheet.

5. Compare the calculated value of PI with 3.14 (standard approximated value of PI).

6. Each group will write down some reasons why they think their calculated value of PI may differ from 3.14, (standard approximated value of PI).


The worksheet should contain the following information:
-Name of object measured.
-Measurement of Circumference of object (in correct units).
-Measurement of Diameter of object (in correct units).
-Calculation of PI as a fraction and a decimal.
-Difference of calculated PI and 3.14 ( standard approximated value of PI).
-Reasons why calculated value of PI may differ from 3.14 (standard approximated value of PI).

Rubric attached.


1. This lesson could easily be condensed or expanded as far as the amount and type of objects used.
2. The measurement in different units also may be used. Just remember larger units of measurement will generally create a greater difference in the standard approximated value of PI.

Attached Files

Worksheet for students and a rubric for worksheet.     File Extension: pdf

Return to the Beacon Lesson Plan Library.