Scale Factor
A rectangle is 4 cm wide and 6 cm long. A similar rectangle has a width of 8 cm. What is the scale factor?
2
(8 ÷ 4)
A recipe uses 2 cups of flour for every 3 cups of sugar. Is this a proportional relationship?
Yes, because the ratio 2:3 is constant.
What is the radius of a circle with a diameter of 10 cm?
5 cm
-3 + 7
4
2x + 5 =11
x = 3
A triangle has a side length of 5 in. Its scaled copy has a side length of 15 in. What is the scale factor?
3
(15 / 5 )
If 5 notebooks cost $12.50, how much would 8 notebooks cost at the same rate?
$20
C.O.P = $2.50
Find the circumference of a circle with a 7 cm. Use 3.14 for pi.
C = 43.96 cm
C = 2 X 3.14 X 7
-6 - 4
-10
3x - 4 = 8
X = 4
A model car is built with a scale factor of 1 :18. If the model car is 10 inches wide, what is the actual car?
180 inches
(10*18)
Zara filled up her car with 15 gallons of gas. If Zara paid $33.00, what was the price per gallon of gas?
$2.20 per gallon
A circle has a diameter of 12 inches. What is the area? Use 3.14 for pi.
A = 113.04 in2
A = r2 X 3.14
-3 X 5
-15
5x - 3x + 2 - 10 = 20
x = 14
A photo is enlarged using a scale factor of 2.5. If the original is 4 inches wide, what is the width of the enlarged photo?
10 inches
(4 * 2.5)
Determine whether the following points form a proportional relationship: (1, 3) (2, 6) (3, 8)
Explain why or why not
No, they do not have the same constant of proportionality.
The circumference of a circle is 31.4 cm. What is the diameter? Use 3.14 for pi
10 cm
4 + (-7) X 2
-10
Solve & graph
3x - 7 < 11
x < 6
graph: open dot on 6 & line goes towards all numbers less than 6
A blueprint has a scale of 1 inch = 4 feet. If a wall on the blueprint is 3.5 inches long, what is the actual length of the wall?
14 feet
(3.5 * 4)
A graph shows a line passing through the origin and (4, 10). Write an equation that represents this proportional relationship.
y = 2.5x
A bike wheel has a radius of 14 inches. How far will it travel in one complete rotation?
87.92 inches
14 X 3.14 X 2
[ (-2) X (-3) ] + [4 - (-5)]
15
Solve & graph
-4x + 5 > 1
x < 1
graph: open dot on 1 & line goes towards all numbers less than 1