import geometry;

size(7.5cm);

show(currentcoordsys);

line axe=line(-.5,2);
triangle t=triangleabc(3,8,10,(5,2)),
         imt=reflect(axe)*t; 
// tri=triangleabc(a=3,b=8,c=10,angle=0,A=(5,2));
// tri est un triangle ABC direct, tel que :
//                     A=(5,2), 
//                     (vec(i),vec(AB))=0,
//                     a=BC=3,b=AC=8,c=AB=10
		 
draw(axe,blue);

show(t);
show("$A'$","$B'$","$C'$",imt);
draw(segment(t.A,imt.A),1bp+red,StickIntervalMarker(2,1));
draw(segment(t.B,imt.B),1bp+blue,StickIntervalMarker(2,2));
draw(segment(t.C,imt.C),1bp+green,StickIntervalMarker(2,3));
perpendicularmark(line(t.A,imt.A),axe);
perpendicularmark(line(t.B,imt.B),axe);
perpendicularmark(line(t.C,imt.C),axe);

addMargins(5mm,5mm);