1. Pre-Algebra Solve the circumference formula C = 2 r for r. Transforming Formulas Lesson 7-7 C = 2 r Use the Division Property of Equality. C2C2 2 r 2 = Simplify. C2C2 = r, or r = C2C2 Additional Examples

2. Pre-Algebra Transforming Formulas Solve the perimeter formula P = 2 + 2w for w. Lesson 7-7 P = 2 + 2w Simplify.P – 2 = 2w Subtract 2 from each side.P – 2 = 2 + 2w – 2 Multiply each side by. 1212 1212 (P – 2 ) = (2w) 1212 1212 P – = wUse the Distributive Property and simplify. Additional Examples

3. Pre-Algebra Transforming Formulas You plan a 600-mi trip to New York City. You estimate your trip will take about 10 hours. To estimate your average speed, solve the distance formula d = rt for r. Then substitute to find the average speed. Lesson 7-7 d = rt Your average speed will be about 60 mi/h. = 60Simplify. Divide each side by t.= dtdt rt t Simplify.= r, or r = dtdt dtdt Replace d with 600 and t with 10.r = 600 10 Additional Examples

4. Pre-Algebra Transforming Formulas The high temperature one day in San Diego was 32°C. Solve C = (F – 32) for F. Then substitute to find the temperature in degrees Fahrenheit. Lesson 7-7 5959 C = (F – 32) 5959 (C) = (F – 32) 9595 9595 5959 Multiply each side by. 9595 Simplify.C = F – 32 9595 Additional Examples

5. Pre-Algebra Transforming Formulas (continued) Lesson 7-7 32°C is 89.6°F. Add 32 to each side. C + 32 = F – 32 + 32 9595 Simplify and rewrite.C + 32 = F, or F = C + 32 9595 9595 Replace C with 32. Simplify. F = (32) + 32 = 89.6 9595 Additional Examples