Letter E is correct.
Area of equilateral trianlge= (1/2) tiime a^2 square root 3
Equation for the base is = x^2+y^2 =9
at x ,
y= square root (9-x^2)
Side of triangle a= 2y
d times Volume = (1/2)a^2 square root 3 dx
d times V= (square root 3) (9-x^2) dx
V= square root 3 INT (9-x^2) dx
-3V= 2square root INT (9-x^2) dx
0
V= 2 square root 3 ( 9x-x^3/3)
V=2 square root 3 ( 27-9)
V= 36 square root 3
The answer is E.
