This is very easy you should read over it again
To answer this question you need to use the Pythagorean theorem. First you substitute the values for a and b. Usually, the value of c represents the hypotenuse in this case c represents the incline of the ramp. As you can see in the following calculations we set a to be the base of the ramp while b is the height of the ram.

We get that the incline of the ramp is about 3.556 meters however we can round it up to be 4 meters. The final answer needs to be given in feet, and 1 meters is 3.28 feet. Therefore to get the answer in feet we do the following calculations:

Therefore the ramp incline should be 13.12 feet.
Adverbial clause is an adverb which is a dependent clause. It's used as an adverb in a sentence to show the time, contrast, conditions, place, reason, concession, purpose or result.
Hope i helped!
he had witnessed during his World War II service.