 # 7.1 Ratio and Proportion Textbook page 357.

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7.1 Ratio and Proportion Textbook page 357

ratio A comparison of a number a and a nonzero number b using division. The ratio of a to b can be written as: a fraction (or an equivalent decimal) as a:b or as “a to b” a b

simplify the ratio 60 cm to 200 cm
Rewrite as a fraction Divide the numerator and the denominator by the greatest common factor Simplify as 60 cm / 20 200 cm / 20 3 cm 10 cm

simplify the ratio 3 ft to 18 in
Rewrite as a fraction Make sure the units are the same, then divide the numerator and the denominator by the greatest common factor Simplify as 3 ft * 12 in = 36 in 18 in in 36 in / 18 18in / 18 2 in 1 in

The perimeter of a rectangle is 84 ft
The perimeter of a rectangle is 84 ft. The ratio of the length to the width is 4:3. Find the length and width of the rectangle. length : width 4 : 3 P = 2l + 2w P = 2(4x) + 2(3x) 84 = 8x + 6x 84 = 14x length ___ ___ 6 6 6 6 6 X = 6 width 6 length = 4(6) = 24 units 6 width = 3(6) = 18 units

Proportions An equation that states that two fractions are equal a = b c d b and c are the means a and d are the extremes Multiply the means and extremes – the cross products are equal. Solve the resulting equation extreme mean mean extreme bc = ad

5 = y 3( y + 2) 3y = 3y = y = 8 5(6) =

Examples on pg 1) EF = 16, FG = 8 3) x = 4 4) y = 9 5) m = 5

Homework Assignment # 3 Pg 361 Problems 1-46, 56-61