EFFECT conpton giving no angle

Nov 2019
1
0
mongolia
A photon undergoing Compton scattering has an energy of 130 keV (1 keV = 1000 eV),after scattering, and the electron recoils with an energy of 45keV. ( 45 kev here mean the kinetic energy of scattered electron)
(a) Find the wavelength of the incident photon.
(b) Find the angle at which the photon is scattered.
(c) Find the angle at which the electron recoils.


i did the calculation found that at:
a) that the wavelength of the incident photon is 0.0953846x10^-10 m
b) i m reaching an answer 1-cosO=2.0809 that is wrong since it s >1 it should be <1
is the question wrong or the calculation at b?