http://img444.imageshack.us/content.php?page=done&l=img444/4990/rectangleq.jpg
In the figure, ABCD is a rectangle of dimensions 12 cm x 5cm. M and N are two points on the sides AB and BC respectively. If MB = (x+2) cm, BN = x cm and the area of MNCD = 36 cm^2, find the value (s) of x.
F4 Maths @@
2009-10-15 1:11 am
回答 (2)
2009-10-16 9:27 am
✔ 最佳答案
MB = (x + 2) cmAM = 12 - (x + 2) = (10 - x) cm
Area MNCD = Area of rectangle - Area ADM - Area BMN
Area of rectangle = 5*12= 60
Area ADM = (1/2)(5)(10- x) = 25 - 5x/2
Area BMN = (1/2)x(x + 2) = x^2/2 + x
Therefore,
60 - (25 - 5x/2) - (x^2/2 + x) = 36
35 + 3x/2 - x^2/2 - 36 = 0
x^2 - 3x + 2 = 0
(x - 2)(x - 1) = 0
x = 1 or x = 2
2009-10-15 6:36 am
the pic can't be shown!! can you fix it?
收錄日期: 2021-04-23 23:19:11
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