Arc lenght dimension in sketch

[Onink]

How can I add an arc lenght dimension in a sketch, to use as a constraint?

I am making a staircase which revolves around a cilinder and I want the sides of the steps to be a certain lenght.

[Chris Hammond]

I'm not sure you can. You can however use math to determine the angle based on arc length and radius. The formula is Arc Length = Angle (in radians) * radius. To rewrite that to solve for the angle in degrees the formula is Angle = (180* Arc Length)/(PI * radius). I tried it out using a parameter for the Arc length and it worked fine. In order for this to work, I had to set the parameter to "no unit" when I created it. Then I could control the arc length based on the parameter. See the attached image.

[Onink]

This does work indeed, but I still wonder if there's an easier way to do this.

Thanks for this solution anyway. For now I will use this.

[Onink]

I found out that there is a lenght parameter where you can measure an element, which turns into a parameter. This way, when the lenght of the element changes, your parameter changes.
And you can use it to measure an arc, but you can't constrain the arc length with this parameter.

Its the snake like button next to the mm2: