66B
Ratios and Proportions
Proportions are used to find _________________________ _____________.
5 dogs
3 cats
=
15 dogs
x
4 sodas
=
7 waters
x
28 waters
3 pencils
There are two ways to set up proportions
1. Using your math facts, identify
equivalent ratios (proportions)
x
=
33 pencils
22 pens
2. Cross-Multiply to identify the
missing number
How to Cross-Multiply:
2.5 cm
1 in
=
27.5 cm
3 feet
=
1 yard
x
x
16.5 yards
Setting Up Proportions
How many inches are in a
foot?
How many quarts are in a
gallon?
How many cm are in a
meter?
5ft. = ________ in.
12qt = ________ gal.
450 cm. = __________ m
If the average person puts uses a 1:3 ketchup If the fish to hermit crab ratio at my house
to mustard ratio on their burgers. If I put 9 tsp is 3 to 4, how many fish should I buy if I plan
of ketchup on my burger, how much mustard on buying two more hermit crabs?
should I put on?
Customary vs. Metric Measurement
Identify if the units are Customary Measurements (C) or Metric Measurements (M)
1) 5 oz.
______
2) 7 mm.
______
3) 5 kL.
______
4) 12 ft.
______
5) 15 kg.
______
6) 3 cm.
______
7) 30 mi.
______
8) 2 g.
______
9) 7 fl. oz.
______
10)
______
11)
______
12)
______
9 lb.
15 T
4 pt.
What is Ballpark Measurement?
Quick conversions between ___________________________ & _________________.
We often use the symbol: ______. Answers are approximations (ballpark), not exact.
Example:
Paige ran a 5km. race. What would be the closest distance she ran in miles?
5km. ≈ ______ mi.
Steps:
1. Set up a ratio using the known measurements.
2. Set up a second ratio with what you know from
the problem.
3. Solve to identify the missing information.
Solving Ballpark Measurements:
1) 2 in ≈ ____ cm
2) 4 liter ≈ ____ quarts
3) 3 oz ≈ ____ grams
4) 2 meter ≈ ____ yards
5) 2 km ≈ ____ mi
6) 3 kilogram ≈ ____ lbs.
Ballpark Measurement (cont’d)
7) ______ g ≈ 78 oz
8) 45 in ≈ ____ cm
9) ______ km ≈ 5 mi
10)
75 cm ≈ ______in.
11)
8 meters ≈ _____ yards 12)
132 lbs ≈ _______ kg
13)
6 km ≈ _______ mi
14)
2 liters ≈ _____ quarts
15)
48 ounces ≈ ______ g
16)
Water boils at 100°C
17) Water freezes at 0°C
and ______ °F
18)
Body temperature is
and _______ °F
about 37°C and _____ °F
11) The distance between Rodney’s house and garage is about 13 meters. What is the
approximate distance in yards?
12) Mrs. Washington estimates that she needs 30 liters of juice for her daughter’s birthday
party. About how many quarts of juice does she need?
You are a world famous safe cracker. When old safes are found or
people lose their combinations, they come to you for help. Use
the clues to help crack the following three safes.
SAFE
CLUES
COMBINATION / CONTENTS
The first number is the boiling point in C.
The combination is: _______, _______, ______
#1
The second number is the approximate number
of yards in 12 meters.
Now open it and see the money inside.
The third number is the approximate number of
liters in 8 quarts.
The first number is the approximate number of
miles in 50 kilometers.
The combination is: _______, _______, ______
Now open it and see the silver inside.
#2
The second number is the freezing point in C.
The third number is the approximate number of
pounds in 31 kilograms.
The first number is the approximate number of
centimeters in 10 inches.
The combination is: _______, _______, ______
Now open it and see the gold bars/coins inside.
#3
The second number is the approximate number
of ounces in 588 grams.
The third number is average room temperature
in F.
Homework
1) Tom’s dad bought a new tent that weighs about 50 pounds. About how many kilograms
does the camper weigh?
2) A scout leader bought 30 quarts of water along for a hike. About how many liters of
water did the troop leader bring?
3) Ms. McCarthy measured a worm on her driveway that was 4 inches long, approximately
what was the length of the worm in centimeters?
4) There are about 250 grams of sugar in a 2 liter bottle of apple juice. About how many
ounces of sugar are in the 2 liter bottle?
5) Harvey bought an apple that weighs 3 ounces. Approximately what is the weight of the
apple in grams?
6) Sandy planted a tree seedling that grows 36 inches each year. About how many
centimeters will the tree grown in 3 years?
7) Which is greater, 10qt. or 8L?
9) Which is longer, 40cm. or 18in?
8) What weighs less, 45 grams or 2 oz?
10)
Which is shorter, 20 mi. or 8 km?
Matching
Measure
Match
A. Body Temperature
1 liter
B. 1 yard ≈
0.6 miles
C. 1 kilometer (km) ≈
20° C
D. Boiling Point
1 meter (m)
E. 1 inch ≈
32° F
F. Room Temperature
212° C
G. 2 pounds (lb) ≈
28 grams (g)
H. 1 ounce ≈
1 kilogram (kg)
I. 1 quart ≈
98° F
J. Freezing Temp
2.5 centimeters