I generally do them by locating the center point, constraining the radius, and then the angle. The angle tool is a little janky specifically on arcs, but it does work. Or if the ends of the arc are fixed to something also immovable, you can just do the radius and angle and use the coincident constraint to stick its endpoints to the ends of other lines and leave the center point alone.

Yours was an interesting approach. I probably would have used a bezier for the pointy end of the heart.