Let the width = X
Then the length would be 2X ( twice the width).
Area is Length x width, so you have X * 2X = 18
x *2x = 2x^2
Now you have 2x^2 = 18
Divide both sides by 2:
x^2 = 9
Take the square root of both sides:
x = sqrt(9)
x = 3
The width is 3 inches.
