Answer:
4.2 inches
Explanation:
The formula to find the area of a rectangle is A=2L+2W
When you plug in the information you already have, the equation is now 42=2(16.8)+2W.
Multiply 2 and 16.8 to get 42=33.6+2W
Subtract 33.6 from 42 and you get 8.4=2W
Divide both sides by 2 and you get 4.2=W