Area of a circle = PI x r^2
Area of sheet = 22/7 x 18^2 = 1,018.29 square cm.
Area of small circle = 22/7 x 4.5^2 = 63.64 square cm.
There are 2 small circles so total area of the circles are 63.64 x 2 = 127.28 square cm.
Area of rectangle = l x w = 4 x 1 = 4 square cm.
Total area of cutouts = 127.28 + 4 = 131.28 square cm.
Area of sheet left, subtract area of cutouts fro area of sheet:
1018.29 - 131.28 = 887.01 square cm.
Round everything as needed.