# 2.7 solving proportions Objective: 1. Solve problems using proportions.

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2.7 solving proportions Objective: 1. Solve problems using proportions

Ratio:A comparison of two numbers, usually written as a fraction. Proportion:--An equation stating that two ratios are equal --(or two equal fractions) Where b ≠ 0 and d ≠ 0. What do you notice happens when you multiply the diagonals on the following proportion?

Please solve for x in each of the following. 3 = x 5 20 12 = x 4 = 10 7 x 17.5 = x 7 = 49 X 56 8 = x 3 (20) = 5(x)7(56) = 49(x)7(10) = 4(x)

solve for x 4 (x – 8) = 5(x + 3) 4x – 32 = 5x + 15 - 5x - 5x______ -1x – 32 = 15 + 32 +32 -1x = 47 x = - 47

Using a proportion to solve a problem. A portable media player has 2 gigabytes of storage and can hold about 500 songs. A similar but larger media player has 80 gigabytes of storage. About how many songs can the larger media player hold? Know Need Plan A portable media player has 2 gigabytes of storage and can hold about 500 songs. A similar but larger media player has 80 gigabytes of storage. About how many songs can the larger media player hold? A portable media player has 2 gigabytes of storage and can hold about 500 songs. A similar but larger media player has 80 gigabytes of storage. About how many songs can the larger media player hold? 2 gigabytes holds 500 songs Larger player has 80 gigabytes Know Need Plan The number of songs the larger player holds Know Need Plan Write a proportion and solve. 2x = 500(80) 2x = 40,000 2 x = 20,000 The larger media player holds 20,000 songs A portable media player has 2 gigabytes of storage and can hold about 500 songs. A similar but larger media player has 80 gigabytes of storage. About how many songs can the larger media player hold?

homework Pg 127: 10-40 evens, 51, 52 Note: showing work is optional through 24, required past that.