program ED;<br/>
uses crt;<br/>

var xa,ya,xb,yb,xc,yc:integer;<br/>

a,b,c,s,pp,p:real;<br/>

Begin<br/>

writeln('vvedi koordinati vershini');<br/>

write('xa='); readln(xa);<br/>

write('ya='); readln(ya);<br/>

write('xb='); readln(xb);<br/>

write('yb='); readln(yb);<br/>

write('xc='); readln(xc);<br/>

write('yc='); readln(yc);<br/>

a:= sqrt(sqr(xb-xc)+sqr(yb-yc));<br/>

b:= sqrt(sqr(xa-xc)+sqr(ya-yc));<br/>

c:= sqrt(sqr(xa-xb)+sqr(ya-yb));<br/>

pp:=a+b+c;<br/>

p:=pp/2;<br/>

s:=sqrt(p*(p-a)*(p-b)*(p-c));<br/>

writeln('p=',pp:5:2);<br/>

writeln('s=',s:5:2);<br/>

readln;<br/>

End.