Answer:
120°; 240°
Step-by-step explanation:
Let's first solve for 
: 
At this point it's just a matter of drawing a circle, and mark where the angle is(please excuse my paint skills, but free hand drawing would be even worse). Red line, is 
on the cosines, and both the green and blue lines are valid solutions. The green line is a quarter of a circle, plus 30°, or 120°. The blue one is 3/4 of a circle, minus 30 degrees, or 240°.
Answer:
Both of these examples are wrong. You cannot add/subtract integers and square roots together, however, you could add square roots together if they have the same number under the square root. For example, 2 - 2√6 will stay as 2 - 2√6 because they aren't like terms. 25 + 5√5 + 5√5 + 5 = 30 + 10√5 because 25 + 5 = 30 and 5√5 + 5√5 = 10√5. We can add 5√5 and 5√5 together because they have the same number under the square root. If we were to compute √2 + √3, we would just leave it as is because they don't have the same number under the square root.
Answer:
The 95% confidence interval for the population proportion of tenth graders reading at or below the eighth grade level is (0.2087, 0.2507).
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of 
, and a confidence level of 
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of 
.
For this problem, we have that:
Suppose a sample of 1537 tenth graders is drawn. Of the students sampled, 1184 read above the eighth grade level. So 1537 - 1184 = 353 read at or below this level. Then
95% confidence level
So 
, z is the value of Z that has a pvalue of 
, so 
.
The lower limit of this interval is:
The upper limit of this interval is:
The 95% confidence interval for the population proportion of tenth graders reading at or below the eighth grade level is (0.2087, 0.2507).
