Setar comma on a return Json

I'm developing an application in C # with API. It will query and show the result. Very simple thing. But in one of my methods it returns the height of the non-comma face. Come for example like this: 175.

Can anyone help me put a comma in the middle? I'm a layman in the C # language.

Thanks

var json = JObject.Parse(result);

            pessoa.altura = (string)json["height"];