View Compilation Error

0_0_6063255_23936\Main.java:11: cannot find symbol
symbol  : variable d
location: class Main
			double result=Math.sqrt((b-a)*(b-a)+(d-c)*(d-c));
			                                     ^
0_0_6063255_23936\Main.java:11: cannot find symbol
symbol  : variable d
location: class Main
			double result=Math.sqrt((b-a)*(b-a)+(d-c)*(d-c));
			                                           ^
2 errors