Answer: 40 cm
So the diagonal formula is - 1/2* (d1*d2) d1 is the first diagonal and d2 is the second diagonal.
So,
1/2 * (18*d2)= 360
18*d2= 360*2
d2= 720/18
d2= 40
A cube is a square shape, so both sides ( length and width) of a face would be the same.
Find the length of the side by finding the square root of the area of the face:
Length = √400 = 20 cm.
Volume is Length x Width X height.
Volume = 20 x 20 x 20 = 8,000 cm^3