The perimeter of a polygon or any shape is just the sum of all of its sides. If you are asked to find the perimeter of a polygon, you would simply just add all the sides together. For example, if a square has 4 sides with the length 2m, the perimeter of that square would be 2m + 2m + 2m + 2m = 8m. Perimeter just means add all the sides.
The answer is D. Linear equation
A quantitative variable is a variable that can be measured i.e. quantified
There can be many sample means as possible
<h3>How to determine the number of samples</h3>
From the question, we understand that the variable is a quantitative variable
This means that the variable can be measured.
When a variable can be measured, there can be many sample means
Hence, the number of sample means is many
Read more about sample means at:
brainly.com/question/7301139
The length of the rectangle is 8 1/2
A-b=21
5a-2b=18
We can use substitution here. Take the first equation and solve for A. (Picking this one because it's easy)
a = 21+b
Plugin to the second equation:5(21+b)-2b=18
Simplify: 105 + 5b - 2b = 18
Simplify: 105 + 3b = 18
Subtract both sides: 3b = 18-105
Simplify: 3b = -87
Divide: b = -29
Plug back into the first: a=21+b
a = 21 - 29
a = -8
Option D
