推 hankboy :感謝 09/14 09:00
※ 引述《hankboy ( 身體健康)》之銘言：
: 有三題，還請教大大們指點，謝謝
: 1.On a turntable, a record of radius 5 inches is rotating at the rate of 45
: revolutions per minute.
: The mumber of inches traveled The mumber of inches traveled per minute by a
: per minute by a point on the record 5 inces from the center of the record.
: circumstance of the record.
: Ans: A
: 2.Circles R,S, and T are in the same plane, have a common center, and have
: radii r, s, and r+s, respectively, where 0 < r < s.
: The area of the region whose πs^2
: boundary consists of circles
: R and T
: Ans: A
先畫圖
A = pi*(r+s)^2-pi*r^2 = pi*s^2 +pi*2rs > pi*s^2
: 3.The sum of the lengths of two sides of isosceles triangle K is 7. K has a
: side of length 4
: The perimeter of K 11
: Ans: D
因為你不知道等邊的哪一邊是3，哪一邊是4
他們的和有可能是3+3+4
也有可能是4+4+3
所以寫D
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