It might be 1/5??
because i'm assuming that the two golden parts on the overlapping triangle equal 1/2 of the overlapping triangle
because the golden parts overlap, the area is not counted twice so therefore there would be 5 halves and since the two golden triangles make one half of the rectangle(that's an assumption!!) so it would be one out of five halves are golden
once agaain i am very unsure of whether that logic is reasonable or not but i believe it's somewhat correct