A circular surface with a radius of 0.057 m is exposed to a uniform external electric field

Question:

A circular surface with a radius of 0.057 m is exposed to a uniform external electric field of magnitude 1.44 × 104 N/C. The magnitude of the electric flux through the surface is 78 N∙ m2/C. What is the angle (less than 90°) between the direction of the electric field and the normal to the surface?