Answer:
Number of square inches glasses = 1788
Explanation:
Formula
Surface area of cuboid = 2(lb + lh + bh)
l - Length of cuboid
b - Breadth of cuboid
h - Height of cuboid
To find the number of glasses needed
Here fish tank is like a open cuboid, we have to find the surface area of top open cuboid.
Here l = 30 in , b = 18 in and h = 13 in
Surface area = 2(lb + lh + bh) - lb
= 2[(30 * 18) + ( 30 * 13) + (18 * 13)] - (30 * 18)
= 2[540 + 390 + 234] - 540
= 2[1164] - 540
= 1788 square inches
Number of square inches glasses = 1788