Transcript Ratio and Proportion - Welcome | Intel Engage

Ratio and Proportion
Prepared by: Josephine Libron
Objectives:
1.
2.
3.
4.
5.
Define ratio and proportion
Identify ways in writing ratios
Find equal ratios
Solve problems involving ratio and
proportion using Microsoft Office
Word.
Make a reflection using PowerPoint
Presentation.
Is it good to compare things?
When quantities have different
measurements, how can they be
compared?
Ratio
- is a comparison of two quantities
Two equal ratios form a PROPORTION.
Ratios and Proportions can be
written as a Fraction. We can also
use the colon ( : ) in writing ratios
and proportions.
Let’s Practice!
Write the ratio or proportion using colon.
1.) 3 cups of sugar for every 5 cups of Flour
2.) 2 men for every 5 cups of rice
3.) 1 book for every 2 pupils
4.) 4/8 = ½
5.) 3/7 = 12/28
Let’s Check!
Click the Button to find the answers.
Answers
1.) 3:5
2.) 2:5
3.) 1:2
4.) 4:8 = 1:2
5.) 3:7 = 12:28
Equal Ratios
To find equal ratios, multiply or divide
the given ratio by a fraction equal to 1.
Examples
1. 2
3
Solution:
Multiply 2 to the given ratio
2
2 x 2 = 4
3
2
6
Therefore, 2 = 4
3
6
2. 8
24
Solution: Divide 8 to the given ratio
8
8 ÷ 8 = 1
24
8
3
Therefore, 8 =
24
1
3
Let’s Practice!
A. Write a ratio equal to each
1.) 1/5
2.) 10/12
3.) 1:2
4.) 2:3
5.) 3:4
Let’s check!
Click the Button to find the answers
Answers
1.) 2
10
4.) 8 : 12
2.) 30
36
5.) 15 : 20
3.) 3 : 6
Let’s Apply
1. Girlie can make five rag dolls from six
discarded socks. Write four ratios equal
to this.
Journal #1
Make a journal about the topic and write
your learning insights.
Proportion
• A proportion is a statement that two ratios
are equal.
• In a proportion, the product of the means
is always equal to the product of the
extremes
=
To find the missing part of the proportion:
• Multiply the given ratio by a fraction equal
to 1 or use the cross product method
• Multiply the means or the extremes. Then
divide by the third given number
Examples:
1.) 8 = 32
7
n
Solution: Use the cross product method
8n= 224
8n = 224 divide both side by 8
8
n = 28
therefore, 8 = 32
7
28
2.) 3 : 5 = n : 25
Solution: Multiply the means or the extremes
3 : 5 = n : 25
3 x 25
5 x n
n
n
=
=
=
=
75
75
75 ÷ 5
15
Let’s Practice
A.
Find n. Use cross products
1. n = 18
2. 5 = 13
10
4
10 n
B.
Find n.
1. 20 : 24 = n : 6
2. 12 : 28 = n : 42
Let’s check!
Click the Button to find the answers
Answers
A.
1. ) 45
2. ) 26
B.
1. ) 5
2. ) 18
Let’s Apply
1. Empty cans sell at P0.75 for 4. How many
does Lina have to sell to earn P11.25?
Solving Problem Involving
Ratio and Proportion
Remember:
There are basic steps in
solving a problem :
Understand, Plan, Carry out
the plan and Check.
Problem
For every 3 metres of bamboo sticks,
three boys can make 5 frames of
Christmas lanterns. How many lantern
frames can they make with 15 metres of
bamboo sticks?
Think
What does the
problem ask
for?
The number of lantern
frames that can be
made from 5m of
bamboo sticks
What are given?
3m of bamboo sticks
3 boys
5 lantern frames
15m of bamboo sticks
Will I need all
the given
numbers
The problem is about
comparing number of
sticks to number of
frames. The number of
boys is not needed.
PLAN
How will I find the Compare the
answer?
number of
metres of
bamboo to
number of
frames.
What is the
number
sentence?
3 = 15
5
n
3
5
Solve
Carry Out
the Plan
Give the
complete
answer
=
15
n
5(15) = 75
3n = 75 ÷ 3
n = 25
The boys can
make 25 lantern
frames
Is the answer
sensible?
Check
Is the
computation
correct?
3 metres can
make 5 lantern
frames. There are
five 3s in 15
5 x 5 = 25
(number of lantern
frames) The
answer is
sensible.
Check
3 x 25 = 75
The
computation is
correct.
Assignment :
Solve : (Show the basic steps in solving a problem.)
1. Three times a recipe calls for 5 cups of milk.
How many cups of milk will be needed for 12 times
the recipe?
2. Two out of three booths sell rag dolls. If there
are 27 booths, how many of these sell rag dolls?
Activities
1. Make a summary of the whole lesson that has
been tackled for the week.
2. Give an example of at least 5 real life problems
involving ratio and proportion with the solutions
following the basic steps in problem solving.
(Write this in the Microsoft Word)
3. Make a reflection based on the lesson for the
whole week using PowerPoint presentation.
Finalization of making PowerPoint
and the Microsoft Word Activities