EXAMPLE 5 Making a Linear Model from a Slope In Figure 4 we have placed a staircase in a coordinate plane, with the origin at the bot- tom left corner. The red line in the figure is the edge of the trim board of the staircase. y (in.) A 40 (36, 32) (a) Find a linear function H that models the height of the trim board above the floor. 32 24 +(12, 16) (b) If the space available to build a staircase is 11 ft wide, how high does the stair- case reach? 16 12 24 36 48 60 x (in.) FIGURE 4 Slope of a staircase

-5 to Model Linear Relationships presents ntities, ant rate value. 4.5 ship is Practice 1. What is the equation of a line that passes through (0.5, 4.25) and (2, 18.5) and has a y-intercept of -0.5? 2. The graph shows the relationship of the number of gallons being drained from an aquarium over time. What function models the relationship? Ay Water level (gal) 80 60 40 20 O 2468 Time (min) X Topic 3 Topic Review 203