<span><span>р₁=π*D₁</span><span>D₁=3,5/π=3,5/3,14=1,115дм </span><span>D₂=1,115*5/7=0,796дм </span><span>р₂</span></span><span><span>=0,796*3,14=2,499дм</span></span>