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Warm Up. 1) 80 girls and boys are planning to go to a Movie. There is a ratio of 6 girls to 2 boys. How many girls are there?
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Warm Up 1) 80 girls and boys are planning to go to a Movie. There isa ratio of 6 girls to 2 boys. How many girls are there? 2) A Chemistry book is comprised of two sections, Organic and non organic in the ratio 2:8. How much of each type of content will be needed to make a book of 400 pages? 3) What is a Scale Drawing/Model?
Warm Up 80 girls and boys are planned for a Movie. There are in a ratio of 6 girls to 2 boy. How many girls are there? 80 x 6/8 = 60 Chemistry book comprises of two section Organic and non organic in the ratio 2:8. How much of each type of content will be needed to make a book of 400 pages? Organic - 400 x 2/10 = 80 Non Organic - 400 x 8/10 = 320 What is a Scale Drawing/Model?
Scale Factor • http://www.virtualnerd.com/pre-algebra/ratios-proportions/similar-figures-indirect-measurement/similar-figures/find-scale-factor-similar-figures
What is the Scale Factor? B 15 5 A 3 9
What is the Scale Factor? B 15 5 A 3 9 ◾The scale factor of figure A to B is: 3 (3 * 3 = 9; 5 * 3 = 15) ◾The scale factor of figure B to A is: 1/3 (9 * 1/3 = 3; 15 * 1/3 = 5) How does the scale factor going from the large figure to the small figure compare to the scale factor of the small figure to the large figure?
Practice • Find the scale factor from the LARGE figure to the SMALL figure. 4 1 1 4
Find the scale factor from the LARGE figure to the SMALL figure. 3 3 18 18 3 18
Find the scale factor from the LARGE figure to the SMALL figure. 6 9 2 3
Find the scale factor from small to large and from large to small for each figure below. Assume figure is similar. 1. 2. 6 24
Percent of Change • The percent of change is the ratio of the amount of change to the original amount. • When an amount increases, the percent of change increases. • When the amount decreases, the percent of change is negative (percent of decrease). • Percent of change = amount of change original measurement