Hello.
The answer is: 24
length=3*width, this can be written as 3w
area=27 sq cm
Formula for the area of a rectangle=27 (area)= 3w (length) * w (width)
27=3w^2
then divide both sides by 3: 9=w^2
take the square root of both sides to get: w=3
Now that we know what the width is, we can substitute that and find the length: 3w= 3*3=24
have a nice day