<PRE><B>Question 109189</B>
Moon Rocks cost $92 per cu yd. What will be the cost of a conical pile of this rock 3 1/3 yd in diameter
 and 2 1/4 yd high? Round to nearest dollar.
:
WE know the volume of a cone: V = {{{(1/3)*pi*r^2*h}}}
:
Let the diameter which is given as: 3 1/3 = {{{10/3}}}
Find the radius: {{{1/2}}} * {{{10/3}}} = {{{10/6}}}= {{{5/3}}}
and
Let the height which is given as: 2 1/4 = {{{9/4}}}
:
V = {{{(1/3)*pi*(5/3)^2*(9/4)}}}
:
V = {{{(1/3)*pi*(25/9)*(9/4)}}}
:
Note that in {{{(25/9)*(9/4)}}} we can cancel the 9: 
V = {{{(1/3)*pi*(25/4)}}}
V = {{{(25/12)*pi}}}
V = 6.545 cu yd
:
Cost = 6.545 * 92 = 602.13 = $602</PRE>