Radius of base = 21cm and its volume = \(\frac{2}3\) × volume of the hemisphere
⇒ \(\frac{1}3\)πr2h = \(\frac{2}3\times\frac{2}3\)πr3
⇒ h = \(\frac{4}3r\) = \(\frac{4}3\times21\) = 28 cm
Hence
surface area of the toy = Surface area of the cone + Surface area of hemisphere
= π r (\(\sqrt{21^2 + 28^2}\)) + 2π r2
= π (21)[35 + 2 × 21]
= 5082 cm2