ic: ratios/proportions hw: pg 174 #6,14,...
TRANSCRIPT
IC: Ratios/ProportionsHW: pg 174 #6,14,
19,22,27 (show work proving your answers!!)
Materials
Write the IC and HW in your planner.
Thursday, 1/10/19
•Homework• Pencil & Grading Pen• Slate, marker, eraser• Ch. 5 Folder
fwmath7.weebly.comUse p.175 #29 (nail
polish) as BW for the next
day after this
x318
(x) (x)
x6
3x
18
-5 -5
x321 3 3
x7
5x316-
3 3
Mrs. Sweet fills 1/3 of a water bottle in 1/6 of a
minute. How much time will it take her to fill the
whole bottle?
bottle
.min
3
16
1
=1
3
1
3
1
1
3
6
1
6
3
2
1
2
1minute
bottle
½ a minute
per bottle
If ratios are proportional they are equivalent. There are
different ways to prove proportionality.
• Reduce to see if the reduced fraction is equivalent
• Calculate to see if the unit rates are the same
• Change both fractions to be written as equivalent, but
non reduced fraction
10
12
50
60
5
6
5
6
22
5
66
151
÷ 5
÷ 54.4
1
1
÷ 15
÷ 154.4
1
20
25
40
50• 2
• 240
50
Ex. 1: Violet is making a batch of purple paint by
mixing red and blue paint in a vat. In the first batch the
ratio of red to blue is 3 gallons to 5 gallons. The next
batch she made she needed a lot more paint, so she
mixed a ratio of red to blue at 12 gallons to 20 gallons.
Would she end up with the same shade of purple? (In
other words…is it proportional?)
red
blue
1st batch
3 gal
5 gal
2nd batch
12 gal
20 gal=?
÷ 4
÷ 4 3
5
3 3
5 5
Yes, the 2nd batch would be the same shade of
purple…just more of it!
Ex. 2: Is 5 inches in 8 hours proportional to
9 inches in 12 hours?
inches
hours
1st
5
8
2nd
9
12=?
5 3
8 4
÷ 3
÷ 3 3
4
Ex. 3: A scale drawing represents the same geometric
shape in a different size. If an object has been scaled
properly the sides remain proportional. Are the sides
of the two rectangles proportional? Was the scale
drawing done correctly?
3 m
7 m
0.75 cm1.75 cm
Actual Scale
height
width
Actual
3
7
Scale
0.75
1.75=?
17
31
43.0
175.1
75.01
43.0
Ex. 3: A scale drawing represents the same geometric
shape in a different size. If an object has been scaled
properly the sides remain proportional. Are the sides
of the two triangles proportional? Was the scale
drawing done correctly?
3 cm
4 cm
7.5 m
10 m
base
height
Big
10
5.7
Small
4
3=?
110
5.7
14
3
1
75.01
75.0
A company is comparing two different cars for their
employees to drive. Use the following chart to see if the
miles per gallon (mpg) is proportional for each of the
cars.
Car Miles on one tank Tank size (gallons)
Chevy Malibu 2016 351 13
Ford Fusion 2016 396 16.5
gallon
miles
Malibu
13
351
Ford Fusion
5.16
396=?
113
351
15.16
396
1
27
1
24
20
8
40
16
Show 3 different ways to prove that these two
fractions are proportional.
Way 1:20
8
Way 2:
Way 3:
2
2 40
16
20
8 4
4 5
2
40
16 8
8 5
2
120
8
140
16
1
4.0
1
4.0