Answer:
The required sample size for the new study is 801.
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:

25% of all adults had used the Internet for such a purpose
This means that 
95% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
What is the required sample size for the new study?
This is n for which M = 0.03. So






Rounding up:
The required sample size for the new study is 801.
So a pentagon is constructed by five identical triangles, that's why you can find the area of one triangle and multiply it with 5:
A_pentagon=A_triangle*5
To find the area of a triangle you must use tangens.
You can watch this for more on that on youtube.
For the length of an arc or a portion of a circle you can find it using:
arc lenght = 2π*r(A/360), where A=angle.
So if you know radians, then 2π is a whole circle. And to calculate for the specific circle you have to use the radius. That's why you multiply with radius, which is the only difference between any two different circles. you then multiply with the part of the circle that you want to find the lenght for, which is A/360 (because there are 360° in a circle)
I hope that helped.
Just replace X with the given value.
X = -3
f(-3) = 5 - (-3)
f(-3) = 5 +3
f(-3) = 8
line N has slope m = 
given a line with slope m then the slope of a line perpendicular to it is
= - 
thus line N has slope -
= 