Finding an unknown in a formula

Water from a full conical flask of radius 4 cm and height 9 cm is poured into a hemispherical bowl and just fills it.

Using the cone volume formula $V = \dfrac{1}{3}\pi r^2h$ and hemisphere volume formula $V = \dfrac{2}{3}\pi R^3$, find the radius $R$ of the hemispherical bowl, in cm, correct to 2 decimal places.