Answer:
The correct option is 3. The required equation is
.
Step-by-step explanation:
It is given that the bottom of the ramp is 12 feet from the truck and the back of the truck is 5 feet high.
Let the length of the ramp be c feet.
The given information forms a right angled triangle. Where bottom of the ramp from the truck is base, height of the back of the truck is perpendicular and length of ramp is hypotenuses.
Base = 12 feet
Perpendicular = 5 feet
Hypotenuses = c feet
Using Pythagoras theorem,


The required equation is
.
Therefore option 3 is correct.