Atoms (Bohr Model)

An electron is revolving in an excited state of a hydrogen atom with velocity sqrt(25.6) x 10^5 ms^-1. The radius of the orbit is x x 10^-9 m. The value of x is: [Take mass of electron = 9 x 10^-31 kg, charge of electron = -1.6 x 10^-19 C and 1/(4 pi epsilon_0) = 9 x 10^9 N m^2 C^-2]