Awater cup in the shape of a cone has a height of 4 inches and a maximum diameter of 3 inches. what is the volume of the water in the cup, to the nearest tenth of a cubic inch, when the cup is filled to half its height?

The diameter of half the cone is equal to half of the given diameter and its height is also half the given height. 
                                   V = 1/3(πr²)(h)
d = 1.5 inches, r = 0.75 inches
h = 2 inches

Substituting,
                                   V = 1/3(π)(0.75 in)²(2 in)
                                          V = 1.178 in³