a). The y-intercept is the point where the graph touches the y-axis.
It's the value of ' y ' when x=0.
The y-intercept of this graph is 4,500 ft.
It's the jumper's altitude at time = zero minutes.
b). The slope of the line is
(change in ' y ') / (change in ' x ')
both over the same part of the graph.
Let's use the whole graph ... the whole slanted line.
' y ' changes from 4,500 ft to zero. The change is - 4,500 feet
' x ' changes from zero to 3 minutes. The change is 3 minutes
Slope = (- 4,500 ft) / (3 min) = - 1,500 ft/minute
According to the slope, the diver is descending (dropping, going down).
The rate of drop is 1,500 ft per minute. Same as 25 ft per second.
c). The x-intercept is the point where the graph touches the x-axis.
It's the value of ' x ' that makes ' y ' be zero.
On this graph, the x-intercept is 3 minutes.
It's the time when the diver reached the ground ... her altitude became zero.
