Program Example1;

{ Program to demonstrate the arccos function. }

Uses math;

Procedure WriteRadDeg(X : float);

begin
  Writeln(X: 8 : 5, ' rad = ', radtodeg(x): 8 : 5, ' degrees.')
end;

begin
  WriteRadDeg (arccos(1));
  WriteRadDeg (arccos(sqrt(3) / 2));
  WriteRadDeg (arccos(sqrt(2) / 2));
  WriteRadDeg (arccos(1 / 2));
  WriteRadDeg (arccos(0));
  WriteRadDeg (arccos(-1));
end.
{https://www.freepascal.org/docs-html/rtl/math/arccos.html}