V=\frac{4}{3}\pi r^3
r_1=6:2=3
r_2=12:2=6
r_3=18:2=9
{V_1+V_2+V_3=\frac{4}{3}\pi *3^3+\frac{4}{3}\pi *6^3+\frac{4}{3}\pi *9^3=\frac{4}{3}\pi(27 +216+729)=\frac{4}{3}\pi *972=1296\pi\ [j^3]}
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\frac{1}{2}*V_4=1296\pi
\frac{1}{\not2^1}*\frac{\not4^2}{3}\pi R^3=1296\pi |:\pi
\frac{2}{3} R^3=1296 |*3
2R^3=3888 |:2
R^3=1944
R=\sqrt[3]{216*9}=6\sqrt[3]9 promień półkuli
{P=\frac{1}{2}*4\pi R^2 +\pi R^2=2\pi R^2+\pi R^2=3\pi R^2=3\pi *(6\sqrt[3]9)^2=3\pi *36\sqrt[3]{81}=108\pi * 3\sqrt[3]3=324\pi * \sqrt[3]3}
\approx 1468 \ [j^2]