Чему равен угол между диагоналями равнобедренной трапеции?

An electron flies into the solenoid at an angle of α = 30 ° to the axis at a speed of v. Having made 10 revolutions, the electron flies out of the solenoid. How did the kinetic energy of the electron change? The field of the solenoid is considered homogeneous along the entire length.