If you're using OpenLayers 3, you may need to use a mix of Vincenty (not in the standard build) and Ellipsoid. Ellipsoid contains
- vincentyDistance
- vincentyInitialBearing
- vincentyFinalBearing
So, given two coordinates, you can get the distance, but you also need the initial bearing/azimuth because you'll need to call Util.DestinationVincenty (pass in 1 coordinate, bearing/azimuth, and 1/3 distance) to get the destination or target coordinate.
Someone more familiar with OpenLayers will probably have a better solution. I cobbled this one together via Google searches.
Note: Geodesy has direct and indirect problems. The direct, or first, problem is: given a coordinate, azimuth and distance, find the target coordinate. The indirect, or second, problem is: given 2 coordinates, find the distance and azimuth between them. Most algorithms for the indirect problem, like Vincenty's, can give you distance and azimuth but not all implementers include the azimuth. The problem is that it's required for the direct problem, like when you want to find points on a geodesic line.