Answer:
Step-by-step explanation:
Given that:
Little Gull Island Lighthouse shines a light from a height of 91 feet above the sea level.
The angle of depression is unknown.
Distance of the point at sea surface from the base of lighthouse is 865 ft.
This situation can be modeled or can be represented as the figure attached in the answer area.
The situation can be represented by a right angled 
in which we are given the base and the height of the triangle.
And we have to find the value of 
(Because they are the internal vertically opposite angles).
Using tangent ratio:
Therefore, the angle of depression is:
Answer:
(5.4k+7.9m+8.1n) centimeters
Step-by-step explanation:
Given the side length of a triangle;
S1 = (1.3k+3.5m) cm
S2 = (4.1k-1.6n) cm
S3 = (9.7n+4.4m) cm
Perimeter of the triangle = S1+S2 + S3
Perimeter of the triangle = (1.3k+3.5m) + (4.1k-1.6n) + (9.7n+4.4m)
Collect the like terms;
Perimeter of the triangle = 1.3k+4.1k+3.5m+4.4m-1.6n+9.7n
Perimeter of the triangle = 5.4k+7.9m+8.1n
Hence the expression that represents the perimeter of the triangle is (5.4k+7.9m+8.1n) centimeters
