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1. 计算涂色部分的周长。(12分)
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答案
1. (1) $100×2+3.14×60=388.4(\mathrm{m})$
(2) $3.14×8×\frac{1}{4}+8÷2+3.14×(8÷2)÷2=16.56(\mathrm{cm})$
(3) $3.14×4=12.56(\mathrm{dm})$
(4) $2×3.14×6+2×6×2=61.68(\mathrm{cm})$
(2) $3.14×8×\frac{1}{4}+8÷2+3.14×(8÷2)÷2=16.56(\mathrm{cm})$
(3) $3.14×4=12.56(\mathrm{dm})$
(4) $2×3.14×6+2×6×2=61.68(\mathrm{cm})$
2. 计算涂色部分的面积。(12 分)
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答案
2. (1) $3.14×(10^2-6^2)=200.96(\mathrm{cm}^2)$
(2) $2×2-3.14×2^2×\frac{1}{4}=0.86(\mathrm{m}^2)$
(3) $3.14×(4÷2)^2÷2-3.14×(2÷2)^2=3.14(\mathrm{cm}^2)$
(4) $3.14×10^2÷4+6×6-(10+6)×6÷2=66.5(\mathrm{cm}^2)$
(2) $2×2-3.14×2^2×\frac{1}{4}=0.86(\mathrm{m}^2)$
(3) $3.14×(4÷2)^2÷2-3.14×(2÷2)^2=3.14(\mathrm{cm}^2)$
(4) $3.14×10^2÷4+6×6-(10+6)×6÷2=66.5(\mathrm{cm}^2)$
