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8-2 The Percent Equation. Standard: PFA N8: Develop algorithms for percent problems and be fluent in their use. The Equation. % · Base = Part (of) (is). Take Note: -Use the decimal form for the %!!
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8-2 The Percent Equation Standard: PFA N8: Develop algorithms for percent problems and be fluent in their use
The Equation % · Base = Part (of) (is) Take Note: -Use the decimal form for the %!! -Whatever the % represents, the part represents -They have to match!!
Example 1 (Missing Part) If 20% of the class is Boys and there are 30 students in the class, how many are boys? % · Base = Part (of) (is) % boys • students = part boys 20% • 30 = b 0.20 • 30 = b 6 = b (Use the equation) (Remember, the part and the percent must match!) (Change the percent to a decimal) (Multiply) (Write a sentence) There are 6 boys (and 24 girls) in the class.
Missing % Joe made 34 shots out of 50 he attempted. What % of shots did Joe miss? % · Base = Part (of) (is) % missed• Shots attempt = Shots missed p • 50 = 16 p •50 = 16 50 50 p = 0.32 Joe missed 32% (made 68%) of his shots. (Use the equation) (The part and the percent must match!) (Use the inverse operation to isolate the variable) or 32% (Change the decimal to percent form to answer the question) Write a sentence.
Missing Base 80% of What Number is 42? % • base = part (of) (is) 80% • b = 42 0.80 • b = 42 0.80• b = 42 0.80 0.80 b = 52.5 80% of 52.5 is 42. (Use the equation) (Change the percent to a decimal) (Use the inverse operation to isolate the variable) (Divide) (Write a sentence)
You Try… 40% of all cell phone users report talking while driving. If 32 people said they talk while driving , how many cell phone users were surveyed? % · Base = Part (of) (is) % talk• cell users = part talk 40% • s = 32 0.40 • s = 32 0.40• s = 32 0.40 0.40 s = 80 80 cell phone users were surveyed. (Use the equation) (Remember, the part and the percent must match!) (Change the percent to a decimal) (Use the inverse operation to isolate the variable) (Write a sentence)
One More… 45% of Mrs. Pettit’s students are boys, and 50% of Mrs. Campbell’s students are boys. If Mrs. Pettit has 140 Students and Mrs. Campbell has 135 students, who has more boys?
Homework • Pg. 342-343 #22-26, 32-43 all