**Topic: **
| Exploring Side Lengths of Triangles |

**Content: **
| This lesson introduces scalene, isosceles, and equilateral triangles and their differences. |

**Goals: **
| The student will be able to identify triangles using the correct terminology based on the measurement of the side lengths. |

**Objectives:**
| TEKS 111.22 Mathematics, Grade 6. Knowledge and Skills (6): Geometry and spatial reasoning. The student uses geometric vocabulary to describe angles, polygons, and circles. |

**Materials:**
| various sizes and shapes of colorful paper triangles; and rulers |

**Introduction:**
| Review properties of right, acute, and obtuse triangles. Break students into groups of four, and pass out ten triangles to each group. Each student should be given a ruler. |

**Development:**
| Define vocabulary terms: scalene, equilateral, and isosceles. Teacher will model activity by examining and measuring triangles (that were passed out to the students) and discussing how to determine what type of triangle it is by measuring side length. |

**Practice:**
| In their groups, students will measure the side lengths of the various triangles and determine whether the triangle is scalene, isosceles, or equilateral. After this, the teacher will discuss the results of each group and answer questions. |

**Checking For Understanding:**
| Review vocabulary learned today and have students guide teacher through one more triangle problem to check for understanding. Reteach any necessary parts. |

**Closure:**
| What did you discover about triangles today? Can right, acute, or obtuse triangles also be scalene, equilateral or isosceles? Tomorrow we will use what we know about triangles to learn how to find the area and perimeter of triangles. |

**Evaluation:**
| same as "Independent Practive" above. |