posted by Angie .
Sophie measured a piece of paper to be 21.7 cm by 28.5 cm. The piece of paper is actually 21.6 cm by 28.4 cm.
Determine the amount of square centimeters in the area of the piece of paper using Sophie's measurements.(I got 618.45 sq cm)
Determine the number of square centimeters in the actual area of the piece of paper. (I got 613.44 sq cm.)
Determine the relative error in calculating the area. Express your answer as a decimal to the nearest thousandth. (I don't know how to do this part.)