To find side $ l $ use Pythagorean Theorem:
$$ r^2 + h^2 = l^2 $$After substituting $r = 22.2\, \text{cm}$ and $h = 19.8\, \text{cm}$ we have:
$$ \left( 22.2\, \text{cm} \right)^{2} + \left( 19.8\, \text{cm} \right)^{2} = l^2 $$ $$ 492.84\, \text{cm}^2 + 392.04\, \text{cm}^2 = l^2 $$ $$ l^2 = 884.88\, \text{cm}^2 $$ $$ l = \sqrt{ 884.88\, \text{cm}^2 } $$$$ l = 29.7469\, \text{cm} $$