Answer:
Following are the responses to the given question:
Step-by-step explanation:

The missing side would be B = 15
Answer:
135 square ft.
Step-by-step explanation:
To solve this equation, you need to find the area of this rectangle. Area is always base x height, or in this case, length x width. Now you multply your length, 15', by your width, 9', to get your answer, 135 square feet. When you multiply two measurments of the same unit together, you get square (units), which simply means that you multiplied two of the same unit of measurment together.
Answer:

Step-by-step explanation:
First, note that

And using the chain rule in one variable

Now remember that the chain rule in several variables sates that

Therefore the chain rule in several variables would look like this.

By using trigonometric relations, we will see that the angle of elevation must be 55°.
<h3>
How to find the angle of elevation?</h3>
We can see this as a right triangle, where one cathetus measures 1250ft (altitude) and the other cathetus measures 875ft.
The angle of elevation is the angle such that the adjacent cathetus is the one measuring 875ft.
Then we can use the relation:
tan(a) = (opposite cathetus)/(adjacent cathetus)
tan(a) = 1250ft/875ft
To find the angle of elevation, we can use the inverse tangent function:
a = Atan(1250ft/875ft) = 55°
The angle of elevation must be 55 degrees.
If you want to learn more about right triangles:
brainly.com/question/2217700
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