Program Dien_tich_hinh_thang;
Uses crt;
Var a,b,c,s:integer;
Begin
clrscr;
write('nhap do dai cua day lon :');
readln(a);
write('nhap do dai cua day nho :');
readln(b);
write('nhap do dai cua chieu cao :');
readln(c);
s:=(1/2)*(a+b)*c
writeln('dien tich hinh thang',s);
readln;
End.