# Lesson 17

Painting a Room

### Lesson Narrative

In this culminating lesson, students make material and cost estimates for a home improvement project, applying and integrating many concepts and skills from the past three units.

Students determine the area of the walls of a bedroom, estimate the amount of paint needed to paint them, and determine the cost associated with the project (MP4). Along the way, they reason about areas of two-dimensional figures, convert units of measurements, solve ratio and rate problems, and work with percentages. Though there is a single correct measure for the total area of the walls to be painted, the amount of paint needed will depend on some assumptions and decisions students make about the work involved. The problem requires students to make some decisions about how to approach the task and which tools to use (MP5).

Depending on instructional choices made, this lesson could take one or more class meetings. The time estimates for the two main activities are intentionally left blank because the time will vary based on instructional decisions made. Variables affecting the amount of time needed include how much guidance and autonomy students are given, how elaborate the presentation of their work is expected to be, and how much time is taken for sharing solutions at the end.

### Learning Goals

Teacher Facing

• Apply rates and percentages to calculate how long it will take and how much it will cost to complete a painting project, and explain (orally) the reasoning.
• Make simplifying assumptions and determine what information is needed to solve a problem about painting a room.

### Student Facing

Let’s see what it takes to paint a room.

### Student Facing

• I can apply what I have learned about unit rates and percentages to predict how long it will take and how much it will cost to paint all the walls in a room.

Building On