三个梯形,高之比1:2:3,上底比6:9:4,下底比12:15:10甲面积为30...
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发布时间:2022-04-25 10:10
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时间:2023-11-13 12:41
设三个梯形的高分别为
h,2h,3h,上底分别为
6x,9x,4x,下底分别为
12y,15y,10y第一个梯形的面积S1
=
(6x+12y)h/2
=
(3x+6y)h
=
30乙梯形:S2
=
(9x+15y)*2h/2
=
(9x+15y)h丙梯形:S3
=
(4x+10y)*3h/2
=
(6x+15y)hS2
+
S3
=
(9x+15y)h
+
(6x+15y)h
=
(15x
+
30y)h
=
(3x+6y)h
*
5
=
150平方厘米