1) The sum and difference of 2 numbers are 37 and 3 respectively. find their product.
2) A metallic cyclinder of radius 10 cm is melted and reformed to 2 smaller identical cylinders while the height is kept unchanged. find the radius of a smaller cylinder.
math 急用
2010-07-26 11:38 pm
回答 (1)
2010-07-26 11:47 pm
✔ 最佳答案
1)Let the two numbers be x and y (x>y)
x+y=37...(1)
x-y=3...(2)
(1)-(2):
2y=34
y=17 and x=3+17=20
So, their product=xy=20*17=340.
2)
Let the height of the original cyclinder be h cm and the radius of small cyclinder be r cm
pi*10^2*h=2(pi*r^2*h)
10^2=2*r^2
r^2=50
r=√50=√25*√2=5√2
So, the required radius is 5√2 cm
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