The water is in the shape of a rectangular prism with a 2 cm by 5
cm base and depth 6 cm.
Therefore, the volume of water is $2
cm} ×5 cm} ×6 cm} = 60
cm}^3$.
A face of the prism having the greatest area has dimensions 5 cm by 8
cm.
When the prism is tipped so that it stands on a 5 cm by 8 cm face, the
water is once again in the shape of a rectangular prism with a 5 cm by 8
cm base and unknown depth.
Suppose that after the prism is tipped, the water’s depth is d cm.
Since the volume of water is still $60
cm}^3whentheprismistipped,then5 cm} ×8 cm} ×d
cm} = 60 cm}^3or40d
cm}^3 = 60 cm}^3,andsod=4060=23$.
When the prism is tipped so that it stands on a face with the greatest
area, the depth of the water is $23 cm}=1.5$ cm.