fir r , raz sferei mici, R, raza sferei mari si Rs raza sferei noi, rezultate
r=8:2=4
R=10:2=5
V=(4π/3)*(2³+5³)=4*(8+125)π/3=4*133π/3 cm³=532π/3 cm³
R s nou obtinute =?
4πRs³/3=4π*133/3
Rs³=133
Rs=∛133≈5,1044cm
arie sferamica/ arie Sfera rezultata= 4πr²/4πRs²=r²/Rs²= (r/Rs)²=[2/(∛133]²≈0,392²≈0,154≈15,4%