1. 2.8 – Proportions & Similar Figures “I can solve proportions using scale factors.” “I can find missing side lengths of similar figures.”

2. VOCABULARY 1.Similar Figures - Figures that are the same shape, but not the same size. Corresponding angles are equal, but the corresponding sides are proportional. 2.Scale – the ratio of any length on a drawing to the actual length

3. Similar Figures This symbol means “similar to” The ratios of all 3 sides are the exact same Each angle is equal to another angle in the same position in the other triangle.

4. Find the missing sides lengths, a and b. First, write a ratio you know 8. 6.4 Next, write a proportion with a side length you need to find. 8 = 7. 6.4 a Last, Cross multiply and solve! 8a = 44.8 a = 5.6 Find length b on your own

5. The sun’s rays strike the building and the girl at the same angle, forming two similar triangles. How tall is the building if the girl is 5ft? -3ft--------15ft-------- girl’s shadow = building’s shadow girl’s height building’s height 3 = 15 5 x 3x = 75 x = 25 The building is 25 feet tall.

6. Class work/Homework You are to complete the Mirror Open Response before you leave. – If you do not finish it, it is homework. Your homework is p. 134 # 6 – 18 (even)