V: volume of a cone = (πr²h)/3 = 104.67 in³
π: pi = 3.14
r: radius = 1/2 diameter = [unknown]
h: height = 4 in
V = (πr²h)/3
V = r²(πh)/3
r² = (3V)/(πh)
r² = (3 ×104.67)/(3.14 × 4)
r² = 25
r = √25
r = 5 (but remember the radius is only 1/2 the diameter)
thus . . .
d = 10 in