Answer:
3.9
Step-by-step explanation:
Formula of Cone volume = [tex]\pi r^{2} \frac{h}{3}[/tex]
Radius = 8.2/2 = 4.1
[tex]68.42=\pi 4.1^{2} \frac{h}{3}[/tex]
[tex]\pi 4.1^{2} \frac{h}{3}=17.6h[/tex]
Divides by both sides by 17.6
68.42/17.6 = 17.6h/17.6
3.8875 = h