The length of a rectangle is two thirds its width. the area is 12 square meters. find its width. round your answer to two decimal places.

L = w
a = 12 
Length times width = area 
L · w = a
w · w = 12
  = 12
Divide both sides by or mulitply both sides by (either one is fine)
÷   = 12 ÷
or
  = 12 
= 18
Square root both sides to get rid of the squared on the w
= 
w = 4.24