Question

下图的比例尺是1:400，图中长方形的长是2.5厘米，宽是1.5厘米，求阴影部分的实际面积是多少平

下图的比例尺是1:400，图中长方形的长是2.5厘米，宽是1.5厘米，求阴影部分的实际面积是多少平方米？

Answer 1

阴影面积是长方形面积的一半
实际长2.5÷1/400=1000厘米=10米
实际宽1.5÷1/400=600厘米=6米
阴影实际面积：10×6×1/2=30平方米

Answer 2

过点O作OE垂直AC,OF垂直BD                                                                                                           又∵四边形ABCD为矩形                                                                                                                    ∴EF在一条直线上                                                                                                                              ∴AC=BD，AB=EF                                                                                                                            又∵比例尺是1:400      AC=2.5cm，AB=1.5cm                                                                                     ∴AC的实际长度为10m，AB的实际长度为6m                                                                                 ∴S△ACO+S△BOC=1/2•AC•OE+1/2•BD•OF=1/2•AC(BD)•(OE+OF)=1/2•AC•AB=1/2×10×6=30m²