The formula of a volume of a cone:
[tex]V=\dfrac{1}{3}Bh[/rex]
B - area of a base
h - height
We have
[tex]V=90\ cm^3,\ B=18\ cm^2[/tex]
Substitute:
[tex]90=\dfrac{1}{3}\cdot18\cdot h\\\\90=6h\qquad|\text{divide both sides by 6}\\\\15=h\to h=15[/tex]
Answer: 15 cm.
