Lesson 41Ratios, Proportions & Similarity

Vocabulary:1. Ratio: a comparison of two values by division.

2. Proportion: a statement that two ratios are equal.

3. Cross Products: multiplying two proportions.

4. Similar Figures: two figures that have the same shape but not necessarily the same size. Angles are congruent; sides are proportional.

5. Similarity statement: a statement indicating that two polygons are similar by listing vertices in order of correspondence.

New Concepts: What is Similarity??

New Concepts: Similar Figures

New Concepts: Similar Figures

New Concepts: Ratios

Example 1: Writing Ratios and Proportions

Example 1: Writing Ratios and Proportions

You Try! Write a ratio in three ways:1. Write three ratios comparing the longest sides.

2. Write three ratios comparing the shortest sides.

New Concepts: Proportions

Example 2: Solving Proportions Using Cross Products

You Try: