Answer:
81
Step-by-step explanation:

9 x 9 = 81
Part a)
The simple random sample of size n=36 is obtained from a population with

and

The sampling distribution of the sample means has a mean that is equal to mean of the population the sample has been drawn from.
Therefore the sampling distribution has a mean of

The standard error of the means becomes the standard deviation of the sampling distribution.

Part b) We want to find

We need to convert to z-score.

Part c)
We want to find

We convert to z-score and use the normal distribution table to find the corresponding area.

Part d)
We want to find :

We convert to z-scores and again use the standard normal distribution table.

Let

, so that

,

, and

. Then

Now let

, so that

. Then

Transform back to

to get

and again to get back a result in terms of

.
Every triangle has a total of 180 degrees. If one angle measure is 100, then 180-100 is 80. This means that the other two angle measures have a total of 80. As angle j and k are equal, we divide 80 by 2, to get 40. This means that the measure of both angle j and k is 40 degrees. The measure of angle j is 40 degrees.