To calculate this you need to imagine triangle which points are:
boat
Top of lighthouse
Bottom of lighthouse
That triangle has 90 degrees angle at bottom of lighthouse. That means that we can use trigonometry to determine length between boat and bottom of lighthouse
tan(25) = 89/x
x = 89/tan(25)
x = 190.86
after rounding, the answer is D, 191 feet
Answer:
0.02275
Step-by-step explanation:
We have been given that the time needed to complete a final examination in a particular college course is normally distributed with a mean of 80 minutes and a standard deviation of 10 minutes. We are asked to find the probability of completing the exam in one hour or less.
We know that 1 hour equals 60 minutes. First of all, we will find the z-score corresponding to 60 minutes.

z = z-score,
x = Sample score,
= Mean,
= Standard deviation.



Now, we will use normal distribution table to find area under z-score of
as:


Therefore, the probability of completing the exam in one hour or less is 0.02275.
Where is the rest of the question?
For this case we must simplify the following expression:

We eliminate the parentheses taking into account that:

We add similar terms taking into account that:
Equal signs are added and the same sign is placed.
Different signs are subtracted and the major sign is placed.

Answer:
