1) A piece of wire of length 36 cm is cut into two parts. One part, x cm long, os bent into a square and the other part is bent into a circle. If the lenght of a side of the square is equal to the radius of the circle, what equations can be used to find x?
2) which of the following is a factor of 2(a-b)^2 - a^2 + b^2? (^2=2次)
A. a+3b
B. a-2b
C. a+b
D. a+3b
E. 3a-b
中4math題..
2009-02-12 4:14 am
回答 (2)
2009-02-12 4:24 am
✔ 最佳答案
1)36-x = perimeter of circle
x = square
each side of square = x/4 = radius of circle
2rπ = perimeter of circle = 36-x
2(x/4)π=36-x
(π/2)x + x = 36
[(π/2) + 1]x = 36
And we can use this equation to find x
2
2(a-b)^2 - a^2 + b^2
=2(a^2-2ab+b^2)-a^2+b^2
=a^2-4ab+3b^2
=(a-3b)(a-b)
So a-3b is a factor of 2(a-b)^2 - a^2 + b^2?
2009-02-12 4:30 am
1.
the length of a side of the square= x/4
the radius of the circle=(36-x)/2Pie(兀)
i.e. x/4=(36-x)/2兀
2兀x=(36-x)(4)
2兀x=144-4x
x= 144/(2兀+4)
=14.0cm
2.
我搵到既factor係(a-3b) and (a-b)-.-"
the length of a side of the square= x/4
the radius of the circle=(36-x)/2Pie(兀)
i.e. x/4=(36-x)/2兀
2兀x=(36-x)(4)
2兀x=144-4x
x= 144/(2兀+4)
=14.0cm
2.
我搵到既factor係(a-3b) and (a-b)-.-"
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