- #1
jrm2002
- 57
- 0
Circular arc--badly stuck
I have a circular arc defined by 3 points [start point, intermediate point an end point].
I know the radius of the circular arc too.
I know the angle subtended by the start and end point at the centre.
I do not know the center of the circle
Now,
I want to calculate the length of the arc using s = r * theta
"r" being the radius and "theta" the angle subtended by the start and end point at the centre.[theta being the smaller included angle]
Now, i get a length "L"
But in some problems my answer is correct value "L" but in some cases the answer i need is 2*pi - L [that corresponding to bigger included angle] but i get "L".This i checked graphically--
Howm to get the correct validation algebraically?
I have a circular arc defined by 3 points [start point, intermediate point an end point].
I know the radius of the circular arc too.
I know the angle subtended by the start and end point at the centre.
I do not know the center of the circle
Now,
I want to calculate the length of the arc using s = r * theta
"r" being the radius and "theta" the angle subtended by the start and end point at the centre.[theta being the smaller included angle]
Now, i get a length "L"
But in some problems my answer is correct value "L" but in some cases the answer i need is 2*pi - L [that corresponding to bigger included angle] but i get "L".This i checked graphically--
Howm to get the correct validation algebraically?