Answer:
1.


2.

Step-by-step explanation:
Solving (1):
Given

Required
Determine the radius and circumference
Radius is calculated as follows:



The circumference is calculated using:



Solving (2):
Given

Assume that the window is circular, the perimeter is calculated as follows:



T is less then or equal to 10 equals 100
(f+g)(x) = f(x) + g(x) = (|x| + 9 ) + (-6) =
|x| + 9 - 6 = |x| + 3
Answer is |x| + 3
The answer to the problem is A) 20 feet below sea level