Let the width be x.
⇒ Width = x
Length is twice the width.
⇒ Length = 2x
The area is 18 cm²
⇒ x(2x) = 18
Solve x:
x(2x) = 18
Distribute x:
2x² = 18
Divide both sides by 2:
x² = 9
Square root both sides:
x = 3
Width = x = 3 cm
Length = 2x = 2(3) = 6 cm
Answer: Width = 3cm