Instead of brainly you could just open your calculator.
10-3.585 = 6.415
Answer:
Margin of error of 0.0485 hours.
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of
.
That is z with a pvalue of
, so Z = 1.96.
Now, find the margin of error M as such

In which
is the standard deviation of the population and n is the size of the sample.
In this question:

The margin of error is of:



Margin of error of 0.0485 hours.
B² - 4ac
= 8² - 4*(-2)*(-9)
= 64 - 72
= -8
36x2(for the total amount of yarn for the width) would be 72. 112-72=40. Since it is a rectangle and the width should both be the same size, the length should be 20 inches. (20+20+36+36=112, so 20 inches is the correct answer.