In many geometry problems, setting a value for EPSILON leads WA, while setting another value for EPSILON leads the solution to get ACCEPTED. It happens that for which value of EPSILON I got ACCEPTED on a problem, with the same value of EPSILON, I got WA on another problem.

For example, on problem 140A - Новогодний стол, I used 1e-6 as the value of EPSILON and got WA then changing the value of EPSILON to 1e-10 got ACCEPTED.

So, I am very confused to set the value of EPSILON.

Can you please help me in such issue?