Answer: 6 feet.
Explanation:
You can observe the the triangle shown in the figure attached is a right triangle, therefore, you can calculate the height of the triangle (which you can call h) as following:
![sin\alpha=(opposite)/(hypotenuse)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6j5eh56eb8lcstqvo7zl1n0flvsxdmjmip.png)
Where:
![\alpha=30\°\\opposite=h\\hypotenuse=12ft](https://img.qammunity.org/2020/formulas/mathematics/high-school/s1pol7hg8xfz0879c0whix3npyf9k8rp2b.png)
Substitute values and solve for the height. Therefor, the result is:
![sin(30\°)=(h)/(12)\\\\h=12*sin(30\°)\\h=6](https://img.qammunity.org/2020/formulas/mathematics/high-school/6yxoa7tfe8db7f2k7j4rmodp41az6uowqd.png)
Then the height of the ramp is 6 feet.