Question

题目在图片上？

这两题怎么算呀

Answer 1

1、如上图将长方形长的两个中点，宽的两个中点连接(图红色虚线)

可知小三角形①②③④面积相等。它们占整个长方形面积的一半，

阴影面积=16/27x1/2÷4×3

=4/18=2/9cm²

2、1/2×1/3+1/3×1/4+1/4×1/5+1/5×1/6+1/6×1/7+1/7×1/8

=1/3(1/2+1/4)+1/5(1/4+1/6)+1/7(1/6+1/8)

=1/3×3/4+1/5×5/12+1/7×7/24

=1/4+1/12+1/24

=6/24+2/24+1/24

=9/24

=3/8。

Answer 2

1、阴影部分的面积=2/27m^2。

2、1/2x1/3+1/3x1/4+1/4x1/5+1/5x1/6+1/6x1/7+1/7x1/8
=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)+(1/7-1/8)
=1/2-1/8
=4/8-1/8
=3/8。

Answer 3

Answer 4