I can compare proportional relationships in graphs, tables, and equations. 

COMPARING PROPORTIONAL RELATIONSHIPS

To compare proportional relationships represented in different ways, find

the unit rate, or the constant of proportionality, for each representation.

The representations below show the rental cost per hour for canoes at three

different shops.

TABLE

Rental Cost ($)     Time (hr)      Rental Cost / Time (hr)

18                  1/2            18 / 0.5 = 36

27                  3/4            27 / 0.75 = 36

36                  1              36 / 1 = 36

54                  1 1/2          54 / 1.5 = 36

Unit rate from the table: $36 per hour.

GRAPH

x-axis: Time (hr)

y-axis: Rental Cost ($)

Labeled points: (2, 50) and (3, 75).

As time increases by 1 hour, rental cost increases by $25.

The straight line passes through the origin.

Unit rate from the graph: $25 per hour.

EQUATION

c = 28t

To find the unit rate, determine the value of c when t = 1.

c = 28(1) = 28

Unit rate from the equation: $28 per hour.

COMPARISON

Table: $36/hr

Graph: $25/hr

Equation: $28/hr

The graph represents the lowest hourly rental cost, followed by the equation,

then the table.