program z57;
{Даны стороны треуг.:a,b,c. Выч. cos углов по теореме
косинусов:sqr(c)=sqr(a)+sqr(b)-2ab*cos(alfa)}
uses crt;
var a,b,c,cosa,cosb,cosc:real;
procedure cos(a1,b1,c1:real;var cosa1:real);
begin
cosa1:=(c1*c1+b1*b1-a1*a1)/(2*c1*b1);
end;
clrscr;
write('a=');readln(a);
write('b=');readln(b);
write('c=');readln(c);
cos(a,b,c,cosa);
cos(b,c,a,cosb);
cos(c,a,b,cosc);
writeln('cosa=',cosa);
writeln('cosb=',cosb);
write('cosc=',cosc);
readln;
end.