Answered by : lorenzo-satta-chiris

readln (a, b, c);
s := (a + b + c)/2.0;
area := sqrt(s * (s - a)*(s-b)*(s-c));
writeln(area); 

Source : https://www.tutorialspoint.com/pascal/pascal_quick_guide.htm | Last Update : Thu, 21 Jan 21