Finding perimeter is simple. All you do is add up all of the side lengths, and bada bing bada boom, you got the perimeter.
Answer:
When two lines are crossed by another line (which is called the Transversal), the angles in matching corners are called corresponding angles. Example: a and e are corresponding angles. When the two lines are parallel Corresponding Angles are equal.
Multiples of 8 are basically the result of counting by 8's. (Technically, multiples are a set of number which can be divided by a certain number without a remainder.)
The first 4 multiples of 8 are {

}.
We can use the points in either order and you will still get the same slope. I usually solve in order that is given. So the first coordinates I label (x1,y1) and the second is (x2,y2).
Slope=m=(y2-y1)/(x2-x1)
m=(9-5)/(3-1)=4/2=2
Slope is 2.