SSAT Elementary Level Quantitative - How to find the perimeter of a rectangle

What is the length of a rectangular room with a perimeter of and a width of

Explanation

We have the perimeter and the width, so we can plug those values into our equation and solve for our unknown.

Subtract from both sides

Divide by both sides

$\frac{50}{2}=\frac{2l}{2}$

Angela has a garden that she wants to put a fence around. How much fencing will she need if her garden is by

Explanation

The fence is going around the garden, so this is a perimeter problem.

What is the perimeter of the rectangle below?

Screen shot 2015 09 29 at 8.31.53 am

Explanation

The formula for perimeter of a rectangle is

To solve for the perimeter we can plug our known values into the equation.

What is the width of the rectangle if the perimeter is and the length is ?

Explanation

The formula for perimeter of a rectangle is

To solve for the width we can plug our known values into the equation.

Subtract from both sides

Divide by both sides

Find the perimeter of a rectangle with width 4 and length 6.

Explanation

To solve, simply use the formula for perimeter. Thus,

If this formula is hard to remember, simply draw a diagram and add up the sides. Remember, there are two widths and two lengths per rectangle so you get w+w+l+l which is equivalent to the formula above.

Screen_shot_2014-02-12_at_9.31.18_pm

What is the perimeter of the above rectangle?

Explanation

To find the perimeter of this rectangle, add all four sides together. Even though we are not given the length of all four sides, we know that opposite sides of a rectangle are always equal!