An open-topped fish tank has a length of 30 inches, width of 10 1/2 inches, and height of 12 inches. What is the volume of the water in the tank if the tank is 3/4 filled? A 945 in
B. 1,287 in
C. 2,835 in
D. 3,780 in​

You have 2 sides that are 2 cms and you have 6 sides that are 1/2 cm and you have 4 sides that are 1 cm. the smallest sides are 1/2 the medium sized sides are 1 and the smallest are 1/2. so to find the perimeter you have to add them all up together so your answer will be 11 cm's