Bài 4
uses crt;
var a,b: integer;
c,s,d:real;
begin
clrscr;
readln(a,b);
if (a>0) and (b>0) then
begin
c:=sqrt(a*a+b*b);
d:=(a+b+c)/2;
s:=sqrt(d*(d-a)*(d-b)*(d-c));
writeln(c:4:2,' ',s:4:2);
end
else writeln('nhap lai');
readln
end.
Bài 5
uses crt;
var r: integer;
s,t: real;
begin
clrscr;
readln(r);
s:=r*r*3.14;
t:=2*3.14*r;
writeln(s:4:2,' ',t:4:2);
readln
end.
bài 6
uses crt;
var a,b,x: INTEGER;
s,v,t: real;
begin
clrscr;
readln(a,b,x);
s:=a*b;
v:=(x*(b-x))/2;
t:=s/2;
writeln(s:4:1);
writeln(v:4:1);
write(t:4:1);
readln
end.