The question is incomplete. Here is the complete question.
Semicircles and quarter circles are types of arc lengths. Recall that an arc is simply part of a circle. we learned about the degree measure of an ac, but they also have physical lengths.
a) Determine the arc length to the nearest tenth of an inch.
b) Explain why the following proportion would solve for the length of AC below: 
c) Solve the proportion in (b) to find the length of AC to the nearest tenth of an inch.
Note: The image in the attachment shows the arc to solve this question.
Answer: a) 9.4 in
c) x = 13.6 in
Step-by-step explanation:
a)
, where:
r is the radius of the circumference
mAB is the angle of the arc
arc length = 
arc length = 
arc length = 9.4
The arc lenght for the image is 9.4 inches.
b) An <u>arc</u> <u>length</u> is a fraction of the circumference of a circle. To determine the arc length, the ratio of the length of an arc to the circumference is equal to the ratio of the measure of the arc to 360°. So, suppose the arc length is x, for the arc in (b):


c) Resolving (b):
x = 
x = 13.6
The arc length for the image is 13.6 inches.
Subtract 510 from 375 because you need to find how many more points that he needs to get
Answer:
the answer for this question is 0.713333333333
Its 4 by the way cause it is
Answer:
He must survey 123 adults.
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 z-score that has a p-value of
.
The margin of error is:

Assume that a recent survey suggests that about 87% of adults have heard of the brand.
This means that 
90% confidence level
So
, z is the value of Z that has a p-value of
, so
.
How many adults must he survey in order to be 90% confident that his estimate is within five percentage points of the true population percentage?
This is n for which M = 0.05. So






Rounding up:
He must survey 123 adults.