Getting Last Point on an ARC() and length of ARC()?

[IamThatGuy]

So I been playing around with this experiment and I am starting to realize how important math is for games. =]

 

A snipplet, I didnt include vars

context.beginPath();context.arc(centerX, centerY, radius, 0, 2 * Math.PI, false);context.fillStyle = 'green';context.fill();context.lineWidth = 3;context.strokeStyle = 'yellow';context.stroke(); context.closePath(); context.beginPath();context.moveTo(centerX - radius, centerY);context.lineTo(centerX - 100, centerY);context.stroke();context.closePath(); context.beginPath();context.arc(centerX, centerY, 100, startAngle, endAngle, counterClockwise); context.lineWidth = 1;  context.stroke();context.closePath();

The outcome:

 

 

Anyone know how if there is a built in function to get the Length of the arc and the last Point of the created Arc?

 

If not, anyone know of a formula for such a thing =0