reserve a,b,c,d for Real;
reserve r,s for Real;

theorem Th77:
  0 < b & a*b <= c implies a <= c/b
proof
  assume
A1: b > 0;
  assume a*b <= c;
  then a*b/b <= c/b by A1,Lm25;
  hence thesis by A1,XCMPLX_1:89;
end;
