錐形大小頭,展開(kāi)是扇形,就是用一塊鐵皮做成一個(gè)大小頭,知道大周直經(jīng)是d1=600,小周直徑是d2=380,高h(yuǎn)=300,求展開(kāi)大周半經(jīng)是多少?要有計(jì)算公式最好?
錐形的母線長(zhǎng)l=(h^2+((d1-d2)/2)^2)^0.5
=(300^2+((600-300)/2)^2)^0.5
=(300^2+150^2)^0.5
=335.41
扇形大圓弧長(zhǎng)C1=PI*d1=PI*600=1884.96
扇形小圓弧長(zhǎng)C2=PI*d2=PI*300=942.48
設(shè)扇形大圓弧半徑為R1,扇形小圓弧半徑為R2.
則：C1/R1=C2/R2
R1-R2=l
1884.96/R1=942.48/R2
R1-R2=335.41
R1=335.41+R2
1884.96*R2=942.48*R1=942.48*(335.41+R2)=316117.22+942.48*R2
942.48*R2=316117.22
R2=335.41
R1=335.41+R2=670.82