6-3 Percent of a Number Course 2 Warm Up Warm Up Problem of the Day Problem of the Day Lesson Presentation Lesson Presentation
6-3
Jan 04, 2016
6-3. Percent of a Number. Course 2. Warm Up. Problem of the Day. Lesson Presentation. 6-3. Percent of a Number. Course 2. Warm Up Multiply. 1. 0.05 20 2. 0.32 15 3. 0.06 25 4. 0.75 18 5. 0.34 76. 1. 4.8. 1.5. 13.5. 25.84. 6-3. Percent of a Number. - PowerPoint PPT Presentation
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6-3 Percent of a Number
Course 2
Warm UpWarm Up
Problem of the DayProblem of the Day
Lesson PresentationLesson Presentation
Warm UpMultiply.
1. 0.05 20
2. 0.32 15
3. 0.06 25
4. 0.75 18
5. 0.34 76
1
4.8
1.5
Course 2
6-3 Percent of a Number
13.5
25.84
Problem of the Day
In a group of 60 triangular and square tiles, 25% are red, and 75% are blue. The ratio of triangles to squares is 1:2. Seventy percent of the squares are blue. Find the number of each kind of tile (red or blue squares or triangles).3 red triangles, 17 blue triangles, 12 red squares, 28 blue squares
Course 2
6-3 Percent of a Number
Learn to find the percent of a number.
Course 2
6-3 Percent of a Number
Course 2
6-3 Percent of a Number
The human body is made up mostly of water. In fact, about 67% of a person’s total (100%) body weight is water. If Cameron weighs 90 pounds, about how much of his weight is water?
Recall that a percent is a part of 100. Since you want to know the part of Cameron’s body that is water, you can set up and solve a proportion to find the answer.
Part 67 = n Part100 90Whole Whole
Find the percent of each number.
Additional Example 1A: Using Proportions to Find Percents of Numbers
Course 2
6-3 Percent of a Number
A. 30% of 5030
100= n
5030 · 50 = 100 · n
1,500 = 100n
1,500 100 100
= 100n
15 = n
30% of 50 is 15.
Write a proportion.
Set the cross products equal.
Multiply.
Divide each side by 100 to isolatethe variable.
Course 2
6-3 Percent of a Number
When solving a problem with a percent greater than 100%, the part will be greater than the whole.
Helpful Hint
Additional Example 1B: Using Proportions to Find Percents of Numbers
Course 2
6-3 Percent of a Number
Find the percent of each number.
B. 200% of 24200100
= n24
200 · 24 = 100 · n
4,800 = 100n
4,800 100 100
= 100n
48 = n
200% of 24 is 48.
Write a proportion.
Set the cross products equal.
Multiply.
Divide each side by 100 to isolatethe variable.
Find the percent of each number.
Try This: Example 1A
Course 2
6-3 Percent of a Number
A. 40% of 4040
100= n
4040 · 40 = 100 · n
1,600 = 100n
1,600 100 100
= 100n
16 = n
40% of 40 is 16.
Write a proportion.
Set the cross products equal.
Multiply.
Divide each side by 100 to isolatethe variable.
Try This: Example 1B
Course 2
6-3 Percent of a Number
Find the percent of each number.
B. 150% of 64150100
= n64
150 · 64 = 100 · n
9,600 = 100n
9,600 100 100
= 100n
96 = n
150% of 64 is 96.
Write a proportion.
Set the cross products equal.
Multiply.
Divide each side by 100 to isolatethe variable.
Course 2
6-3 Percent of a Number
In addition to using proportions, you can find the percent of a number by using decimal equivalents.
When you are solving problems with percents, of usually means “times.”
Helpful Hint
Find the percent of the number. Estimate to check whether your answer is reasonable.
Additional Example 2A: Using Decimal Equivalents to Find Percents of Numbers
Course 2
6-3 Percent of a Number
A. 9% of 80
9% of 80 = 0.09 · 80
= 7.2
Estimate
10% · 80 = 8, so 9% of 80 is less than 8. Thus 7.2 is a reasonable answer.
Write the percent as a decimal and multiply.
Additional Example 2B: Using Decimal Equivalents to Find Percents of Numbers
Course 2
6-3 Percent of a Number
Find the percent of the number. Estimateto check whether your answer is reasonable.
B. 3% of 12
3% of 12 = 0.03 · 12
= 0.36
Estimate
5% · 12 = 0.6, so 3% of 12 is a little less than 0.6. Thus 0.36 is a reasonable answer.
Write the percent as a decimal and multiply.
Try This: Example 2A
Insert Lesson Title Here
Course 2
6-3 Percent of a Number
Find the percent of the number. Estimate to check whether your answer is reasonable.
A. 21% of 50
21% of 50 = 0.21 · 50
= 10.5
Estimate
20% · 50 = 10, so 21% of 50 is a little more than 10. Thus 10.5 is a reasonable answer.
Write the percent as a decimal and multiply.
Try This: Example 2B
Course 2
6-3 Percent of a Number
Find the percent of the number. Estimateto check whether your answer is reasonable.
B. 6% of 18
6% of 18 = 0.06 · 18
= 1.08
Estimate
5% · 20 = 1, so 6% of 18 is close to 1. Thus 1.08 is a reasonable answer.
Write the percent as a decimal and multiply.
Additional Example 3: Geography Application
Course 2
6-3 Percent of a Number
The estimated world population in 2001 was 6,157 million. About 40% of the people were 19 or younger. What was the approximate number of people 19 or younger, to the nearest million?
Find 40% of 6,157 million
0.40 · 6,157
2,462.8
The number of people 19 or younger was about 2,463 million.
Write the percent as a decimal.
Multiply.
Try This: Example 3
Course 2
6-3 Percent of a Number
The estimated world population in 2001 was 6,157 million. About 60% of the people were above 19 years of age. What was the approximate number of people 19 or older,to the nearest million? Find 60% of 6,157 million.
0.60 · 6,157
3,694.2
The number of people 19 or older was about 3,694 million.
Write the percent as a decimal.
Multiply.
Lesson Quiz
Find the percent of each number.
1. 25% of 8
2. 40% of 110
3. 150% of 96
4. 0.3% of 120
5. Whitmer Middle School has 850 students. If 42% of the students bought lunch on Monday, how many student bought lunch on Monday?
44
2
Insert Lesson Title Here
144
0.36
Course 2
6-3 Percent of a Number
357
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