[tex]d=\frac{m}{V}\\\\
V=\pi r^{2}H\\[/tex][tex]d=\frac{m}{\pi r^{2}H} \ \ \ |*\pi r^{2}H\\\\
d \pi r^{2}H=m \ \ \ |:d \pi H\\\\
r^{2}=\frac{m}{d \pi H}\\\\
r=\sqrt{\frac{m}{d \pi H}}\\\\
2r=d\\\\
d=2\sqrt{\frac{m}{d \pi H}}[/tex]
[tex]H=43cm\\
d=2.33\frac{g}{cm^{3}}\\
m=3kg=3000g\\\\
d=2\sqrt{\frac{m}{d \pi H}}=2*\sqrt{\frac{3000g}{2.33\frac{g}{cm^{3}} * \pi * 43cm}}=2*\sqrt{\frac{3000}{100,19\pi \frac{1}{cm^{2}}}}\approx6,17cm[/tex]