Similar Figures and Solving Proportions
Learn how to solve proportions using cross multiplication and explore the concept of similar figures having congruent angles and proportional sides.
Similar Figures and Solving Proportions
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Presentation Transcript
Solving Proportions Review • Before we can discuss Similar Figures we need to review how to solve proportions…. • Any ideas?
Solving Proportions • Solving Proportions: You must cross multiply and solve for the missing value. • x • 35 • 2 • 5 • = • 2(35) • = • 5x • 70 • ____ • 5 • = • 5x • ____ • 5 • x = 14
Proportions Practice • x = 14 • r = 28 • k = 45 • z = 9 • d = 66 • s = 72 • w = 36 • t = 12 • a = 24 • f = 14 • h = 18 • c =135 • z = 60 • k = 16 • n = 15
Similar Figures • Similar Figures: have the same shape but are not the same size. • Corresponding Angles of Similar Figures: are congruent. • Corresponding Sides of Similar Figures: are in proportion.
Naming Similar Figures • When naming similar figures, list the corresponding sides and the angles in the same order. • For example, ∆ABC ~ ∆DEF Corresponding Angles • <A & <D • <A & <D • <A & <D Corresponding Sides • AB & DE • BC & EF • AC & DF
Corresponding angles E B 82◦ 82◦ D 43◦ 55◦ F 43◦ 55◦ A C Corresponding sides Similar Figures (~) • Two Figures are Similar if: • Corresponding angles are congruent • Corresponding sides are in proportion