Answer:
Option C is correct.
Step-by-step explanation:
Let x be the distance cover by Michelle
Given:
A circle diameter is 3 miles.
And Michelle biked around the trail 4 times.
We know that
The circumference of a circle.
circumference = 
----------(1)
where 
miles
Put 
and r value in equation 1.
The circumference of a circle is 9.42 miles.
And Michelle biked 4 times, that is equal to 4 
circumference.
.
That is equal to 38 miles.
Therefore, Michelle biked around 4 trail is 38 miles.
It's D, because the mean doesn't matter as much if it's only taken in a small variability. The mean was selected from 25 random pages in the book, that is why it is right.
For lines to be parallel, the slopes have to be the SAME.
For lines to be perpendicular, the slopes have to be the exact opposite. (opposite sign and number)
For example(perpendicular):
slope is 2
the perpendicular slope is -1/2
slope is -4/5
the perpendicular slope is 5/4
12. line a and b are perpendicular
13. Line a: y = 3/5x + 1
Line b: y = 3/5x - 2/5
Line c: y = 4/6 + 5/3x
line a and b are parallel
14. Line a: y = 3x + 6
Line b: y = 6 - 3x
Line c: y = 2/3x + 6
Neither, none of them are parallel or perpendicular
15. Line a: y = -2/3 + 4/3x
Line b: y = -1/4 - 3/4x
Line c: y = 5 + 3/4x
line a and b are perpendicular
Algebra is a very important branch of math.
Algebra is a lot like arithmetic which means it follows all the rules of arithmetic, and it still uses the four main operations that arithmetic is built on.
In arithmetic, the only thing that was unknown was the answer to the problem. For example, 39 + 2 = 41. In algebra, we use a variable to represent the number. A variable is a letter that represents any number. The most common variable is "x".
