Constant of Proportionality
What letter represents the constant of proportionality?
k
What letter represents slope?
m
Write an equation for a line with a constant of 1/4 and a y-intercept of 0
y=1/4x
Dunkin charges $2.75 for a refresher. Starbucks charges $3.50 for a refresher. Who charges more? How much more?
Starbucks charges $0.75 more for a refresher.
How do we find the constant of proportionality?
k=y/x
Slope is the same as...
Constant
or
Unit rate
Netflix charges a sign-up fee of $20 and it costs $12 a month to keep your subscription. Write an equation that represents this situation.
y=12x+20
The equation y=4x represents the cost per Big Mac at McDonalds, where y represents total cost, and x represents number of Big Macs purchased. Whoppers at Burger King cost $2.50 each. Who charges more for a burger? How much more?
McDonalds charges $1.50 more for a burger than Burger King.
Identify the constant of proportionality in this equation y=2/3x
k=2/3
A line which is decreasing has a _________ slope.
Negative
Write the equation of the line whose slope is 6 and y-intercept is -7.
y=6x-7
Ryan runs 3 miles in 27 minutes. The equation y=11x represents Rickie's rate where y represents total distance, and x represents number of miles. Who runs at a faster rate? How much faster?
Ryan runs at a faster rate, 2 minutes faster than Rickie.
Brandon's phone bill costs $30 each month. What is the unit rate or constant of proportionality?
$30
or
k=30
How do you find slope when given two points or ordered pairs?
m= y2-y1/x2-x1
I read 20 pages of my book each night. Write an equation that represents this situation where y is total number of pages read, and x is number of nights.
y=20x
Two friends, Quentin and Olivia, took summer jobs. The equation y=21.50x represents Quentin's earnings in dollars and cents, y, for working x hours. Olivia earned $457.20 in 18 hours. Who makes more money per hour? How much more?
Olivia makes $3.90 more than Quentin per hour.
At Kroger, 6 pounds of chicken thighs costs $52.50. What is the unit rate or constant of proportionality?
k=8.75
or
$8.75 per pound of chicken
Find the slope of the line containing the points (2, 5) and (7, 9)
m=4/5
Katie's phone plan costs $200 to start. There is a $50 monthly charge for service. What is the total cost for x months?
y=50x+200
Hudson was comparing the price of orange juice at two stores. The equation y=0.57x represents what Hudson would pay in dollars and cents, y, for x bottles of orange juice at store A. Hudson can buy 17 bottles of orange juice at Store B for a total cost of $13.26. How much more is a bottle of orange juice at Store B than at Store A?
1 bottle of orange juice costs $0.21 more at Store B than at Store A.