Graphing Proportions

The graph shows a proportional relationship between the total number of tennis balls and the number of cans. What does the point (2,6) represent in this situation?

• 3 cans contain 6 balls.

• 6 cans contain 2 tennis balls.

• There are 2 tennis balls in 6 cans.

• There are 6 tennis balls in 2 cans.

• There are 12 tennis balls in 6 cans.

The graph shows a proportional relationship between the number of miles Marco bikes and the number of hours. What equation relates the distance, y, and the time, x?

• y = 15x

• y = 5x

• k = y/x

• y = (1/15)x

Which graph is a proportional relationship that passes through the point (2,1)?

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A graph is a straight line through the point (0, 5). Can the graph represent a proportional relationship?

• Yes; since the constant of proportionality is 5.

• Yes; the equation of the line can be written in the form y = kx, where k = 5.

• Yes; the graph is a straight line that crosses the y-axis at (0, 5).

• No; the graph of a proportional relationship must pass through (0, 0).

Melanie buys 2 shells for $0.80. Rosi buys 3 shells for $1.20. Carlos buys 4 shells for $1.60. Use the graph to determine whether there is a proportional relationship between the number of shells and their cost.

• Proportional

• Not proportional

Melanie buys 2 shells for $0.80. Rosi buys 3 shells for $1.20. Carlos buys 4 shells for $1.60. Use the graph to determine whether there is a proportional relationship between the number of shells and their cost. If so, what does the constant of proportionality mean in this situation?

• The graph is not proportional

• $0.20

• $0.40

• $0.80