(a)the radius of the innermost electron orbit of the hydrogen atom

(a)the radius of the innermost electron orbit of the hydrogen atom is 5.3$\times { 10 }^{ -11 }$m .Calculate its radius n=3 orbit.
(b)The total energy an electron in the first excited state of hydrogen atom is -3.4eV.find outs its (i)Kinetic energy and (ii)Potential energy
in this state?