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标题: thanks to tongxun and another question [打印本页]

作者: 回家过年    时间: 2002-11-20 17:38     标题: thanks to tongxun and another question

80.R,T,U are points on a circle with a radius of 4, the arc RTU has a length of
4/3pai, what's the length of segment RTU?
[确认]4
作者: tongxun    时间: 2002-11-20 22:12

弧所对的圆心角=X
360/X = 2PAI*4/(4/3PAI)
X=60
由圆心O向弦RU做一垂直线,交于A点。则ROA为一直角三角形。其中,角AOR=30。由于,OR是半径,所以=4,则RA=2,由于半径垂直平分弦,所以弦RU=2*2=4
作者: 回家过年    时间: 2002-11-20 23:01

THANK U
斑竹,segment RTU的意思就是。玄RU 吗




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