中间部分为一长方形
面积=55200.0000*54986.5596
下面主要计算弓形面积:
已知:弦长m,弦高为h
设:弓形所在圆半径为r,则在图形中的直角三角形中有
(m/2)²+(r-h)²=r²,则r=(m²+4h²)/(8h);
设:扇形圆心角为α,则在图形中的直角三角形中有
sin(α/2)=(m/2)/r=(m/2)/((m²+4h²)/(8h))=(8mh)/(m²+4h²);
则α/2=arcsin((8mh)/(m²+4h²)),α=2arcsin((8mh)/(m²+4h²));
则弓形面积S为:
S=S扇形-S三角形
=(αr²/2)-(m(r-h)/2)
=(arcsin((8mh)/(m²+4h²))((m²+4h²)/(8h))²)-(m(((m²+4h²)/(8h))-h)/2)
=(arcsin((8mh)/(m²+4h²))((m²+4h²)/(8h))²)-(m(m²-4h²)/(16h))
即弦长为m,弦高为h的弓形面积S为:
S=(arcsin((8mh)/(m²+4h²))((m²+4h²)/