PSAT Math : How to find the perimeter of a rectangle
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Example Questions
Example Question #201 : Geometry
A rectangle has a width of 2x. If the length is five more than 150% of the width, what is the perimeter of the rectangle?
6x2 + 10x
5x + 10
5x + 5
10(x + 1)
6x2 + 5
10(x + 1)
Given that w = 2x and l = 1.5w + 5, a substitution will show that l = 1.5(2x) + 5 = 3x + 5.
P = 2w + 2l = 2(2x) + 2(3x + 5) = 4x + 6x + 10 = 10x + 10 = 10(x + 1)
Example Question #11 : Rectangles
Note: Figure NOT drawn to scale
Refer to the above figure, which shows a rectangular garden (in green) surrounded by a dirt path (in orange). The dirt path is seven feet wide throughout. Which of the following polynomials gives the perimeter of the garden in feet?
The length of the garden, in feet, is 
The width of the garden, in feet, is 
The perimeter, in feet, is twice the sum of the two:
Example Question #11 : Rectangles
Note: Figure NOT drawn to scale
Refer to the above figure, which shows a square garden (in green) surrounded by a dirt path (in orange) eight feet wide throughout. What is the perimeter of the garden?
The inner square, which represents the garden, has sidelength 
Example Question #11 : Rectangles
Farmer Dave has a rectangular field that is 50 yards wide and 40 yards long. He wants to enclose the field with a wire fence. How much wire does Farmer Dave need?
180 yards
200 yards
170 yards
160 yards
210 yards
180 yards
To solve this problem, find the perimeter of the rectangle. There are two sides that each measure 50 yards and two sides that each measure 40 yards. Together these four sides measure 180 yards.
Example Question #3 : How To Find The Perimeter Of A Figure
A rectangular garden has an area of 
We define the variables as 
We substitute these values into the equation for the area of a rectangle and get 
Lengths cannot be negative, so the only correct answer is 
Therefore, 
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