Interpreting Proportional Relationship Graphs

• 43
• 32.5
• 21.5
• 10.75

• $20
• $30
• $40
• $50

If x represents minutes and y represents gallons of water in a container, which line represents the container that is filling the fastest?

• a

• b

• d

• e

If x represents time and y represents meters a person walks, which line represents the person who is walking faster?

• A

• B

• They are walking the same speed.

• There is not enough information given.

Answer explanation

Even though the graph for A is higher, they are going up at the same rate.

How can you tell if a graph represents a proportional relationship? (select all that apply)

• It is a straight line

• It goes through the origin

• The line is curvy

• The line starts at 10.

What is the unit rate for the rain fall?

• 2 cm per hour

• 1 cm per hour

• ¹/₂ cm per hour

• 4 cm per hour

Answer explanation

Remember that unit rate is the same as constant of proportionality (C.O.P.)

What is the Constant of Proportionality?

• k=46

• k=92

• k=2

• not proportional

Answer explanation

To find the C.O.P. pick a point and divide the Y value by the X value.

The coordinate of point A is (6,60). What is the cost of electricity per hour?

• $60

• $20

• $10

• $6

What does the point (0,0) represent in context of the situation?

• No cookies were sold.

• No money is made selling cookies.

• No money is made when selling two cookies.

• No cookies were sold and no money was made.

Which graph shows a proportional relationship between x and y?

• F

• G

• H

• J