I think the equation is still the same as a non-right triangle. a=(w*l)/2
As long as it's a triangle, that would be the equation. This is because for finding the area for a square or rectangle (quadrilateral) is always a=w*l, that means that the equation for any triangle is always a=(w*l)/2. The division by 2 for the triangle's equation is there because a triangle is half of a quadrilateral. So you would have to divide the quadrilateral's equation by two. Hope I helped :)
