Question

已知弦长7米,拱高0.5米,求弧长是多少

Answer 1

^2=3.5^2+(r-0.5)^2

3.5^2+0.5^2-r=0

r=12.5

sin(a/2)=3.5/12.5=7/25

a/2=16.3

a=32.6度

弧长=12.5*π*32.6/180=7.11米