Question

知道弦长9.6弦高3求弧长

Answer 1

知道弦长L=9.6弦高H=3求弧长C?

弧半径为R,弧所对的圆心角为A.

R^2=(R-H)^2+(L/2)^2

R^2=R^2-2*R*H+H^2+L^2/4

2*R*H=H^2+L^2/4

R=H/2+L^2/(8*H)

=3/2+9.6^2/(8*3)

=5.34

A=2*ARC SIN((L/2)/R)

=2*ARC SIN((9.6/2)/5.34)

=128.02度

=128.02*PI/180

=2.2344弧度

C=A*R

=2.2344*5.34

=11.932