Answer:
<em>120 degrees</em>
Step-by-step explanation:
Find the diagram attached.
From the diagram;
Interior angles are m∠BCA and m∠ABC
Exterior angle is m∠DAB
The sum of interior angle of the triangle is equal to exterior
m∠BCA +m∠ABC =m∠DAB
Given
m∠ABC = 70
m∠BCA =50
m∠DAB = 70 + 50
m∠DAB = 120 degrees
<em>Hence the measure of m∠DAB is 120 degrees</em>
A. The term "units" refers to the measurements in the original question or problem. When looking at the question, the units we are measuring are dollars/feet.
B. In this case, the f'(x) means we are looking for the cost (in dollars) to drill the next foot down.
C. Since the cost increases the more feet we drill down, the sign of f'(x) is positive.