Answer:
0.000298 = 0.0298% probability that the system will collapse
Step-by-step explanation:
Number of possible ways the system can fail:
2 lines from a set of 3 fail, or all three fail.
Two from a set of 3:
Can be A and B, A and C, or B and C. Three possible outcomes then.
The probability of each is:
0.01*0.01*0.99
Two failling, each with 0.01 probability, and 1 working, with 0.99 probability.
All three:
Each with 0.01 probability.
a) What is the probability that the system will collapse
Both cases, so

0.000298 = 0.0298% probability that the system will collapse
<h3>
Answer: Choice B</h3>
Explanation:
Cosine is positive in quadrants I and IV, but quadrant IV isn't shaded in so we can rule out choice A.
Sine is positive in quadrants I and II. So far it looks like choice B could work. In fact, it's the answer because sin(pi/6) = 1/2 and sin(5pi/6) = 1/2. So if 0 ≤ sin(x) < 1/2, then we'd shade the region between theta = 0 and theta = pi/6; as well as the region from theta = 5pi/6 to theta = pi.
Choice C is ruled out because tangent is positive in quadrants I and III, but quadrant III isn't shaded.
Choice D is ruled out for similar reasoning as choice A. Recall that 
Using the Pythagorean triples, one side is 3 units long, one side is 4 units long, and one side is 5 units long. To find the area of a right triangle, multiply length times width. Then divide total by two.
So,
(3•4)/2= 6 units
After scaling units, you should get 24 units.