I need integer positions
This is a probably a design flaw... There's no way you can use these intersections as integers unless you can guarantee the shapes will always intersect on round coordinates. To guarantee your intersections always have integer coordinates, you'll have to limit your triangles to (45º 45º 90º) or create some complex angle-position rules to fit your problem...
I don't really know in what context this intersections are going to be used and can't say much without really seeing the context.
But you could pretty much cast the resulting coordinates to integer, after all the math; but it will wield less accurate positions. If your problem allows you to use approximations of these intersections and your shapes are big enough to reduce the relative difference, you'd probably do fine without the decimals. But you can't use integers when calculating these intersections as, as @slayemin said, the results could vary enormously from the correct values.
But the better option, based on my limited understanding of your problem, would be to fix the design and use floating point numbers instead.