(3)梯形上底6cm,下底 10cm,如果臉積是56cm2?
要梯形既高
設梯形既高是y cm
(4)丙同丁兩數之和是90,已知丙數為丁數的9倍要甲數
我想問幾條方程式 (要部睪同條式 )
2007-09-17 7:21 pm
回答 (2)
2007-09-17 7:33 pm
✔ 最佳答案
(3) (6 + 10) Y = 56 x 2y = 112 / 16
y = 7
(4) x + 9x = 90
10x = 90
x = 9
x 係丁數
2007-09-17 7:37 pm
(3) 你可以把梯形分成一個長方形跟兩個三角形！
rectangle area = 6y
sum of two triangle = (10-6)*y / 2 = 2y
therefore, total area = 8y = 56
then y = 7
(4) if 丁is d, then 丙 is 9d
coz 丁+丙 = 90
therefore, d +9d = 10d = 90
then d = 9
丁 = 9 , 丙 = 81,,
但我不知道甲和丙丁的關係，算不到！
rectangle area = 6y
sum of two triangle = (10-6)*y / 2 = 2y
therefore, total area = 8y = 56
then y = 7
(4) if 丁is d, then 丙 is 9d
coz 丁+丙 = 90
therefore, d +9d = 10d = 90
then d = 9
丁 = 9 , 丙 = 81,,
但我不知道甲和丙丁的關係，算不到！
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