Answer:
Part 1) The exact value of the arc length is 
Part 2) The approximate value of the arc length is 
Step-by-step explanation:
step 1
Find the circumference of the circle
The circumference of a circle is equal to

we have

substitute


step 2
Find the exact value of the arc length by a central angle of 150 degrees
Remember that the circumference of a circle subtends a central angle of 360 degrees
by proportion

step 3
Find the approximate value of the arc length
To find the approximate value, assume

substitute

The length of material needed for the border is the perimeter of the backyard play area
<h3>How to calculate the
length of
material needed </h3>
The area of the play area is given as:

The area of a trapezoid is calculated using:

Where L1 and L2, are the parallel sides of the trapezoid and H represents the height.
The given parameter is not enough to solve the length of material needed.
So, we make use of the following assumed values.
Assume that the parallel sides are: 25 feet and 31 feet long, respectively.
While the other sides are 10.2 feet and 8.2 feet
The length of material needed would be the sum of the above lengths.
So, we have:


Using the assumed values, the length of material needed for the border is 74.4 feet
Read more about perimeters at:
brainly.com/question/17297081
We know that
The formula for combinations is
C=n!/[(n-r)!*r!]
where
n is the total number of objects you choose from
r is the number that you choose to arrange
in this problem
n=15 students
r=4 students
C=15!/[(15-4)!*4!]-----> C=15!/[11!*4!]---> (15*14*13*12*11!)/(11!*4*3*2*1)
C=(15*14*13*12)/(24)----->C=1365
the answer is
1365
1.9 is the answer. But I could be wrong though.
Answer:
"line" a straight line graph is always linear once the line isn't straight, it'll no longer be called a line and will never be linear anymore