《2025年黄冈小状元同步计算天天练六年级数学下册北师大版》

1. 下图刚好能组成圆柱，求圆柱的表面积和体积。

$24.84 = \pi d + d$
$= (\pi + \_\_)d$
$d = 24.84\div(\pi + 1)$
$=$
$=$
$C = \_\_ - d$
$=$
$=$
$r = d\div2$
$=$
$=$
$h = 2d$
$=$
$S_{底}=\pi r^{2}$
$=$
$=$
$S_{表}=2S_{底}+S_{侧}$
$=$
$=$
$=$
$V_{圆柱}=S_{底}\times h$
$=$
$=$
$=$

答案： 24.84 = πd + d
= (π + 1)d
d = 24.84÷(π + 1)
= 24.84÷4.14
= 6(dm)
C = 24.84 - d
= 24.84 - 6
= 18.84(dm)
r = d÷2 = 6÷2 = 3(dm)
h = 2d = 2×6 = 12(dm)
S底 = πr²
= 3.14×3²
= 28.26(dm²)
S表 = 2S底 + S侧
= 2×28.26 + 18.84×12
= 56.52 + 226.08
= 282.6(dm²)
V圆柱 = S底×h
= 28.26×12
= 339.12(dm³)

2. 下图刚好能组成圆柱，求圆柱的表面积和体积。

$51.4 = \pi d + 2d$
$= (\_\_ + \_\_)d$
$h = d =$
$=$
$=$
$S_{侧}=\pi dh$
$=$
$=$
$r = d\div2 =$
$S_{底}=\pi r^{2}$
$=$
$=$
$S_{表}=2S_{底}+S_{侧}$
$=$
$=$
$=$
$V_{圆柱}=S_{底}\times h$
$=$
$=$
$=$

答案： 51.4 = πd + 2d
= (π + 2)d
h = d = 51.4÷(π + 2)
= 51.4÷5.14
= 10(cm)
S侧 = πdh
= 3.14×10×10
= 314(cm²)
r = d÷2
= 10÷2
= 5(cm)
S底 = πr²
= 3.14×5²
= 78.5(cm²)
S表 = 2S底 + S侧
= 2×78.5 + 314
= 157 + 314
= 471(cm²)
V圆柱 = S底×h
= 78.5×10
= 785(cm³)