1.In the figure , the area of recteangle ABCD is 32cm² . The length of AB is twice of AD. Fing the lengths of AB and AD.
2.In the figure , the area of rectangle ABCD is 96cm² . If the length of AB is 1.5times that of AD, find the lengths of CD and BC.
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2008-03-26 8:08 am
回答 (2)
2008-03-26 8:24 am
✔ 最佳答案
第一條:let AD be x,then AB is 2x.
x(2x)=32cm²
2x²=32
x²=16
x=4
Therefore,AB=8cm,AD=4cm
第二條:
let AD be x,then AB is 1.5x.
x(1.5x)=96cm²
1.5x²=96
x²=64
x=8
AB=12cm,AD=8cm
Since the figure is a rectangle,
AB=CD and AD=BC
therefore,CD=12cm and BC=8cm
參考: 自己
2008-03-26 8:24 am
1. Let length of AD be x. Then length of AB is 2x.
Area of ABCD = 32 = x (2x)
therefore 2x^2 = 32
x^2 = 16
x = 4
i.e. AB = 8 cm ; AD = 4 cm
2. In the same sense. Let AD = y , AB is 1.5y
y (1.5y) = 96
1.5y^2 = 96
y^2 = 64
y = 8
i.e. CD = AB = 12
BC = AD = 8
Area of ABCD = 32 = x (2x)
therefore 2x^2 = 32
x^2 = 16
x = 4
i.e. AB = 8 cm ; AD = 4 cm
2. In the same sense. Let AD = y , AB is 1.5y
y (1.5y) = 96
1.5y^2 = 96
y^2 = 64
y = 8
i.e. CD = AB = 12
BC = AD = 8
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