Câu hỏi 38

\(\begin{array}{l} + \,\,{S_{mat\,cau}} = 16\pi {a^2} \Leftrightarrow 4\pi {R^2} = 16\pi {a^2} \Leftrightarrow {R^2} = 4{a^2} \Leftrightarrow R = 2a.\\ + \,\,V = \dfrac{4}{3}\pi {R^3} = \dfrac{4}{3}\pi .{\left( {2a} \right)^3} = \dfrac{{32\pi }}{3}{a^3}.\end{array}\)

Chọn B