Lesson objective: Compute scale drawing dimensions using scale factors.

This lesson helps to build procedural skill with scaling figures up or down. A rectangle is used here because it supports student understanding of changing dimensions without changing proportions. This work develops students' understanding that scale drawings may be larger, smaller or the same size as an original figure.

Students engage in Mathematical Practice 4 (Model with mathematics) as they compute the dimensions of a scale drawing given different sizes of scale factors.

**Key vocabulary:**

- original figure
- proportional
- scale drawing
- scale factor

**Special materials needed:**

- Optional: have students resize a picture using a computer or other device.