立体图形的表面积和体积(2)1: ⑴ 50x30=1500(平方米) ⑵ 50x30+50x2x2+30x2x2 =1500+200+120 =1820(平方米) ⑶ 50x30x2=3000(立方米)2:0.8x0.8x6=3.84(平方米) 0.8x0.8x0.8x1000x0.72=368.64(千克)3:0.8x0.8x1.5=0.96(立方米) 0.8x0.8x2+0.8x1.5x4 =1.28+4.8 =6.08(平方米)4:表面积3.14x1x2+(3.14x1x2)x(3.14x1x2) = 3.14x1x2(3.14x1x2)x(3.14x1x2) =6.28+39.4384 =45.7184(平方分米) 体积3.14x1x(3.14x1x2) =3.14x1x(3.14x1x2) =19.7192(立方分米)5: 12.56÷3.14÷2=2(米)3.14×2x1.2x1/3x750x75%=3.14×4 |