如图,AB是半圆O的直径,OB是半圆C的直径,半圆O的弦AE切半圆C于F,若AE=8,求三角形BCE的面积
2个回答

连接CF,则CF⊥AE

∵BE⊥AE

∴CF∥BE

∴AF/AE = CF/BE = AC/AB

设OC = r,则AB = 4r

∵AE = 8

∴AF = 6,EF = 2

△ACF勾股定理得

AC² - CF² = AF²

即(3r)² - r² = 6²

∴r = 3√2/2,即CF = 3√2/2

∴BE = 2√2

S△BCE = S△ABE - S△ACE

= 1/2(AExBE - AExCF)

= 1/2AE(BE - CF)

= 1/2x8x(2√2 - 3√2/2)

= 2√2