Unit 5 Lesson 12 Similar Triangles Standard NS
- Slides: 12
Unit 5, Lesson 12 Similar Triangles Standard: NS 1. 2, MG 1. 3 Objective: Students find the missing side of similar triangles by using proportions.
Similar Figures • Similar Triangles: same shape, different size! • Characteristics of Similar Triangles – Corresponding angles are equal – Ratios of corresponding sides are equal
Similar Triangles B 6 Same shape, Similar - different sizes!. 8 10 C Angles A L 3 N 4 M 5 Proportional Sides = = 8 6 10 = = 4 3 5 2: 1 ratio Scale factor = 2
Similar Triangles B A L C • M N To find the Scale Factor: 1) Find the corresponding (matching) sides 2) Write a ratio and simplify.
Similar Triangles B A L C • N To find the missing side(s): 1) Find the corresponding (matching) sides 2) Write a proportion or use a ratio table. 3) Solve the proportion. M
Similar Triangles x 6’ 20’ 4’ • Use proportions to solve similar triangle problems.
Problem-Solving • A building casts a 240 meter shadow. At the same time, a 2 meter pole casts a 8 meter shadow. What is the height of the building?
Similar Triangles 14. 5 6’ x’ • Solve for x. 12’
Problem-Solving • A 40 meter building casts a 80 meter shadow. At the same time, a pole casts a 5 meter shadow. What is the height of the pole?
Find the missing sides. Q 2) S x R 8 in. y 7 in. 5 in. 4 in. T U 5 4 = x 8 7 4 = y 8 4 x = 40 4 4 x = 10 4 y = 56 4 4 y = 14
Find the missing sides. x = 20 1) 5 H I J 12 3 4 L 12 y =16 K 5 3 = x 12 4 3 = y 12 3 x = 60 3 3 x = 20 3 y = 48 3 3 y = 16
REVIEW 1) What is the definition of similar triangles? 2) How do you solve similar triangle problems? ’ 3) Where would this be useful in the real world?