I am attempting to find the distanceIf you know the radius (distance from the center to a vertex, see figure above) D ckly by e ath ng... yes I do know the radius, but - am using my smartphone , and I'm not seeing a figure above.

I am attempting to find the distanceIf you know the radius (distance from the center to a vertex, see figure above) D ckly by e ath ng....yes I do know the radius, but - am useing my smartphone , and I'm not seeing a figure above.

Assuming you mean a circle, to find the central angle(theta) when the radius and chord are known, use the formula for chord length and solve for theta.

L=2Rsin(\frac{\theta}{2})

Therefore, {\theta}=2sin^{-1}\left(\frac{1.5825}{R}\right)

Plug in your known radius, R, and you have it.