7.2 Ratios and proportions

Two figures that are ~ have equal angles and proportional sides. Concept #1 Similarity ~ Two figures that are ~ have equal angles and proportional sides.

Example #1 ABCD~WXYZ Name the equal angles and the extended side proportion lengths

Example #2 ABCD~WXYZ Find all angles and side lengths Find the scale factor from small –big and big –small A 14 B 98◦ 100◦ W 42 12 X 17 95◦ D 15 C Z Y

Concept #2 Labels of ratios in pictures The ratio in a picture of any type must include a x variable. The sides of a hexagon are the ratio of 1:2:3:5:6:7.

Example #3 The angles of a triangle are the ratio 2:3:4. Draw the figure. Find all the angles.

Example #4 The angles of a Quadrilateral are the ratio 3:4:6:7 . Draw the figure. Find all the angles.

How to use proportions? Example #4 The sides of a rectangle are the ratio 2:5. Draw a picture. If the perimeter is 70 inches, find the length and width.

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