A cone of height 9 cm with diameter of its base 18 cm is carved out from a wooden solid sphere of radius 9 cm. The percentage of the wood wasted is : Choose the correct choice from the following:  A) 45%  B) 56%  C) 67%  D) 75%  E) None of these
Explanation:   We will first subtract the cone volume from wood volume to get the wood wasted.   Then we can calculate its percentage.   Sphere Volume =4/3πr3   Cone Volume =1/3πr2h   Volume of wood wasted =(4/3π∗9∗9∗9)−(1/3π∗9∗9∗9)=π∗9∗9∗9cm3   Required Percentage =π∗9∗9∗9 /4/3π∗9∗9∗9∗100%=3/4∗100%=75%   Option 75%
<result>D</result>
A cone of height 9 cm with diameter of its base 18 cm is carved out from a wooden solid sphere of radius 9 cm. The percentage of the wood wasted is :