Given:
The center of the circle is at (0,0).
The circle passes through the point A(4,-3).
To find:
The radius and the equation of the circle.
Solution:
Distance formula:
The radius of the circle is the distance between the points (0,0) and (4,-3).
So, the radius of the circle is 5 units.
The standard form of a circle is
Where, (h,k) is center of circle and r is the radius.
Putting h=0, k=0, r=5, we get
Therefore, the radius of the circle is 5 units and the equation of the circle is .
Answer:
We need a sample size of at least 383.
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 .
The margin of error is:
85% confidence level
So , z is the value of Z that has a pvalue of
, so
.
How large a sample would be required in order to estimate the fraction of tenth graders reading at or below the eighth grade level at the 85% confidence level with an error of at most 0.03
We need a sample size of at least n.
n is found with
Then
Rounding up
We need a sample size of at least 383.