Me . i don't understand this section

What you do is that you use your algebraic magic to find your c value. First, you will divide both sides by 5. Now you have 2b= the square root of c +2. Now subtract 2 from both sides and you will have 2b-2= the square root of c. To undo the square root of c, you will need to square it, so square both sides and you have your answer. Good luck!

11/2.2 = 5 inches for the length 8.5/2.2= 3.86 inches for the width