Point("A",1,2) ;
Point("B",-1,1) ;
Point("C",2,-1) ;
Segment("s1","A","B");
Segment("s2","B","C");
Segment("s3","A","C");
Perpendicular("s1","d1","C");
Perpendicular("s2","d2","A");
Intersection("H","h1","h2");