# Lesson 15

Weighted Averages

### Lesson Narrative

In this lesson, students partition segments in given ratios. They begin by calculating midpoints, then attempt more difficult ratios in the subsequent activities. They’re introduced to a weighted average and asked to connect weighted averages to segment partitioning. Finally, they link segment partitioning to concepts of similarity transformations from earlier units. In each case, students are presented with a problem with little direction and expected to make sense of the problem and find a strategy on their own (MP1).

### Learning Goals

Teacher Facing

- Calculate the coordinates of a point on a line segment that partitions the segment in a given ratio.

### Student Facing

- Let’s split segments using averages and ratios.

### Learning Targets

### Student Facing

- I can calculate the coordinates of a point on a line segment that partitions the segment in a given ratio.

### CCSS Standards

### Print Formatted Materials

Teachers with a valid work email address can click here to register or sign in for free access to Cool Down, Teacher Guide, and PowerPoint materials.

Student Task Statements | docx | |

Cumulative Practice Problem Set | docx | |

Cool Down | Log In | |

Teacher Guide | Log In | |

Teacher Presentation Materials | docx |