Well they give you 70"and 75" all triangles 180" so 70+75-180=35"and that is all the big triangle complete now a flat line is also 180" so
35+78-180=67" and then you have a 90" angle too so you just have to 67+90-180=23" and to solve for x do the same thing... Again 23+90-180=67"
Y=23"
X=67"
Hope this helps;D