Foundations of College Algebra Chapter 2 Linear Equations

Foundations of College Algebra Chapter 2 Linear Equations Ratios and Proportions Lesson 2. 6 Objective Day 1 I will learn to words into a ratio, solve a proportion and an equation using.

Definition ratio – a comparison of two quantities with the of measure using division. If the units are not the same to the units of the numerator Ways to write a ratio of number a to number b: 1. a to b 2. a : b 3. a b

Translating words into ratios Step 1 – place first number in. place second number in. Step 2 – check that denominator units are as numerator. If not CONVERT! 1. The ratio of 5 hr to 3 hr: 2. The ratio of 6 hrs to 3 days: 3. The ratio of 3 days to 2 weeks 4. The ratio of 12 hours to 4 days

Definition: proportion – two that are equal. it is a special type of. if a proportion is then the cross products MUST be EQUAL. a = c proportion, b and d ≠ 0 b d ad = bc cross products are equal Be Careful: The cross product property is true when there is more than one term on one side. x +2=3 2 or x +1 = 5 3 4 7

Determine if the following proportions are true or false. a. 3 = 15 4 20 b. 6 = 30 7 32 c. 21 = 62 15 45 d. 13 = 17 91 119

Cross product property can be used to solve for a missing value of a proportion. Step 1: the original proportion down. Step 2: the cross products. Step 3: the linear equation for the variable. Solve the proportion: 5 = x 9 63 Step 1: Write 5 = x 9 63 Step 2: Calculate 5 · 63 = 9 x Step 3: Solve 315 = 9 x ; x = 35 9 9

Cross product property can be used to solve for a missing value of a proportion. Step 1: Write the original proportion down. Step 2: Calculate the cross products. Step 3: Solve the linear equation for the variable. Solve the proportion: x = 35 6 42 7

Cross product property can be used to solve for a missing value of a proportion. Step 1: Write the original proportion down. Step 2: Calculate the cross products. Distribute if necessary Step 3: Solve the linear equation for the variable. Solve the proportion: x – 2 = x + 1 5 3 8

Cross product property can be used to solve for a missing value of a proportion. Step 1: Write the original proportion down. Step 2: Calculate the cross products. Distribute if necessary Step 3: Solve the linear equation for the variable. Solve the proportion: x + 6 = 2 2 5

Homework Page 146 Day 1: 3 – 12; 22 – 26; 29, 31, 32, 34, 35, 38, 41, 42, 43 Update Vocabulary 10