Answer:
The unit rate of change is 9 units.
Explanation:
We have to draw a line which represents a proportional relationship between d and t. In the graph t is represented on x-axis represents and d is represent on y-axis.
It is given that increase of 0.2 units in t corresponds to an increase of 1.8 units in d.
The unit rate of change is also known as slope.
![Slope=\frac{\text{Change in y}}{\text{Change in x}}](https://img.qammunity.org/2019/formulas/mathematics/middle-school/9cgc4snsd3tupq8jzfm35j20iwf1qr98yv.png)
For the given case,
![Slope=\frac{\text{Change in d}}{\text{Change in t}}](https://img.qammunity.org/2019/formulas/mathematics/middle-school/r6dvmwg6khrnr2os8osuj8n511184c0cjz.png)
![Slope=(1.8)/(0.2)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/xvob422tpwvrah2vnc8caqumxipexj6t8g.png)
![Slope=9](https://img.qammunity.org/2019/formulas/mathematics/middle-school/ri99wzizk1p1u73s790kkb5z6cj57d1zof.png)
Therefore the unit rate of change is 9 units.
There is a proportional relationship between d and t, therefore the line must be passing through (0,0).
The point slope form of a line
![y-y_1=m(x-x_1)](https://img.qammunity.org/2019/formulas/mathematics/college/lob8zuuisy2ohheuctatxwwco4ukatcrj3.png)
Where m is the slope.
![y=9x](https://img.qammunity.org/2019/formulas/mathematics/middle-school/i9gc65hl67nc1al6ytc5jwl5gwhqqoswsk.png)
Therefore the equation of line is
.