math
posted by Stacey Graham .
how to solve for radius of horizontal curve with coordinates(NE) for points A,B, C on the curve
Point A : N1405.4018
E1256.7569
Point B : N1283.3703
E1294.7027
Point C : N1225.9373
E1286.6137

If a line is horizontal, it is not a curve and the radius is infinity. What are the units of your numbers?
Your question does not make sense to me. 
its an arc definition curve with pts A, B, C and have to find the radius of the curve

The center of the circle containing those three points is located where the perpendicular bisectors of AB and BC intersect. Get the equations of the bisectors and solve for their intersection point.