弦长L=36米,弦中心到弧顶H=7米,求这个弧型面积?
弧半径R=(L^2+4*H^2)/(8*H)
=(36^2+4*7^2)/(8*7)
=1492/56
=26.643米
圆心角=2*ARC SIN(L/(2*R))
=2*ARC SIN(36/(2*26.643))
=2*ARC SIN(0.6756)
=42.5*2
=85度
弧型面积=PI*R^2*A/360-L*(R-H)/2
=3.1416*26.643^2*85/360-36*(26.643-7)/2
=526.541-353.574
=172.967平方米