View Compilation Error

0_0_30886497_26533.cpp: In function 'int main()':
0_0_30886497_26533.cpp:14:26: error: 'd' was not declared in this scope
         printf("%.3lf\n",d*d*sum/2);
                          ^
0_0_30886497_26533.cpp:14:30: error: 'sum' was not declared in this scope
         printf("%.3lf\n",d*d*sum/2);
                              ^