Do now Homework: Lesson check 2-8 page 133 Warm-up: Add these words to your vocabulary section of your notebook 14. Similar Figures: 2 figures that have the same shape but not necessarily the same size 15. Scale drawing: an enlarged or reduced drawing similar to an actual object or place 16. Scale: ratio of length in a scale drawing to the length of the actual 17. Scale model: a 3-dimensional model that is similar to a 3- dimensional object

HW Questions?

Quiz Review 3 4 = 𝑥 5 3 7 = 𝑥+4 35

Quiz review 8 p = 3 10 3 3b+4 = 2 b−4

Quiz review If 5 lb of pasta salad serves 14 people, how much pasta salad should you bring to a picnic with 49 people?

Quiz Time!

2-8 Proportions and similar figures

Table of contents 1 Page # topic date ? 2-1 Solving One-Step Equations 2/11/15 ? 2-2 Solving Two-Step Equations 2/12/15 ? 2-3 Solving Multi-Step Equations 2/17/15 ? 2-4 Solving Equations with 2/18/15 Variables on Both Sides ? 2-5 Literal Equations and Formulas 2/19/15 ? 2-6 Ratios, Rates & Conversions ? 2-7 Solving Proportions ? 2-8 Proportions & Similar Figures 1

What are similar figures? Similar figures have the same shape but not necessarily the same size.

Similar figures in real life!

If we know the figures are similar, what else do we know?

In the diagram, ∆𝐴𝐵𝐶~∆𝐷𝐸𝐹. What is the length of DE?

Indirect measurement

Applying similarity The sun’s rays strike the building and the girl at the same angle, forming the two similar triangles shown. How tall is the building?

You Try! A man who is 6 ft tall is standing next to a flagpole. The shadow of the man is 3.5 ft and the shadow of the flagpole is 17.5 ft. What is the height of the flagpole? Step 1: draw a picture Step 2: set up a proportion and solve

How else can we use similar figures in real life? Scale drawings are drawings that are similar to an actual object or place. Examples: Floor plans Blueprints Maps

Scale The scale of the drawing is the ratio of any length on the drawing to the actual length.

Interpreting scale drawings What is the actual distance from Jacksonville to Orlando? Use the ruler to measure the distance from Jacksonville to Orlando on the map.

You try – interpreting scale drawings The distance from Jacksonville to Gainesville on the map is about 0.6 inches. What is the actual distance from Jacksonville to Gainesville?

Interpreting scale drawings If you know that the actual distance between two cities is 250 miles and that the cities are 2in apart on a map, how can you find the scale of the map?

How is a scale model different than a scale drawing? A scale model is a 3D model that is similar to a 3D object?

Scale models

Using scale models A giant model heart is shown below. The heart is the ideal size for a person who is 170 ft tall. About what size would you expect the heart of a man who is 6 ft tall to be?

You try! A scale model of a building is 6 in tall. The scale of the model is 1 in : 50 ft. How tall is the actual building?