如图,圆管内原有积水的水面宽AB=40cm,水深EF=10cm,当水面上升10cm,（即EG=10cm）时,水面的宽CD是多少cm（精确到0.1cm）?图在mhtml:file://C:\Documents%20and%20Settings\new\Local%20Settings\Temporary%20Internet%20Files\Con

Question

如图,圆管内原有积水的水面宽AB=40cm,水深EF=10cm,当水面上升10cm,（即EG=10cm）时,水面的宽CD是多少cm（精确到0.1cm）?
图在
mhtml:file://C:\Documents%20and%20Settings\new\Local%20Settings\Temporary%20Internet%20Files\Content.MSO\WordWebPagePreview\1186CEB1.mht

Answer 1

设圆管的半径为Xcm,
根据勾股定理得
（X-10)^2+20^2=X^2
X=25
(1/2CD)^2=25^2-(25-20)^2=600
CD^2=2400
CD=49.0cm