Lesson Plan : Understanding Pi

**Teacher Name: **
| Christina Prindle |

**Grade:**
| Grade 7-8 |

**Subject:**
| Math |

**Topic: **
| Mathematics/Pi |

**Objectives:**
| Students will:
*Measure the circumference of an object to the nearest millimeter.
*Measure the diameter of an object to the nearest millimeter.
*Explain how the number 3.14 for pi was determined.
*Demonstrate that by dividing the circumference of an object by its diameter you end up with pi.
*Discover the formula for finding circumference using pi, and demonstrate it. |

**Materials:**
| *round objects (jars, lids, edc.)
*measuring tape or string and rulers
*paper
*pencil
*calculator |

**Introduction:**
| Students tend to memorize, without understanding formulas that we use in geometry or other mathematic areas. This activity allows students to discover why pi works in solving problems dealing with finding circumference. |

**Practice:**
| 1. Divide class into groups of two.
2. Give materials to student teams.
3. Have student teams make a table or chart that shows name or number of object, circumference, diameter, and answer.
4. Have students measure and record each object's circumference and diameter, then divide the circumference by the diameter and record result in the answer column.
5. Have students find the average of the answer column and compare to other groups in the class to determine a pattern. Students can then find the average number for the class.
6. Explain to the students that they have just discovered pi, which is very immportant in finding the circumference of an object.
7. Have students come up with a formula to find the circumference of an object knowing only the diameter of the object, and the number that represents pi. Students must prove their formula works by demonstration and measuring to check their results. |

**Checking For Understanding:**
| Students must write their conclusions for the activities they have just done. Students may also share what they have learned with other members of the class. Also they must answer three problems listing only the diameter of each object and have them find the circumference. |