I have point c, which represents the center of a circle. After I drag the circle, I want its y coordinate hmm to snap to a line that's drawn between point a and b. How do I solve for hmm?

So far I've been able to find the midway y value between points a and b. However, it's not taking into account point c's x value.:

const snapYToLine = (aY, bY) => {
  const yDist = bY - aY;
  return aY + (yDist * 0.5);
}

const a = { x: 10, y: 10 };
const b = { x: 50, y: 30 };
const c = { x: 20, y: 0 }; // not doing anything with this yet...

const hmm = snapYToLine(a.y, b.y); // will need to include c.x here...
console.log(hmm);