如图,AB是圆O的直径,弦CD交AB于P点∠APD=45°,AP=5,PB=1求CD长
人气:247 ℃ 时间:2019-08-20 17:02:02
解答
过O作OE⊥CD于E
连接OD
∵AP=5,PB=1
∴AB=5+1=6
∵AB是圆O的直径
∴OD=OB=3
∵PB=1
∴OP=2
∵∠APD=45°
∴OE=√2
∴ED²=OD²-OE²
=9-2
=7
∴ED=√7
CD=2√7为什么OE=√2等腰直角三角形,斜边是直角边的√2倍你用勾股定理可以得出
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