Answer:
Length of the ramp, l = 31.22 feet
Step-by-step explanation:
It is given that,
A doorway is 2.45 ft above the ground, AB = 2.45 ft
Angle between the ground and the ramp is,
![\theta=4.5^(\circ)](https://img.qammunity.org/2020/formulas/physics/college/2scmvxt8e88ou7wpw33a72htnpm0uos0jo.png)
Applying trigonometry,
![sin\theta=(AB)/(AC)](https://img.qammunity.org/2020/formulas/physics/college/jb12thfaawwx0iwap0kael4lgiehh7v59n.png)
![AC=(AB)/(sin\theta)](https://img.qammunity.org/2020/formulas/physics/college/kgbrejrv3e9txersvw0uyrgmjpxirp5r45.png)
![AC=(2.45)/(sin(4.5))](https://img.qammunity.org/2020/formulas/physics/college/sr21f26tz35mgchbfl0nm5nyxpdwg1dlyb.png)
AC = 31.22 ft
So, the length of the ramp is 31.22 feet. Hence, this is the required solution.