Provided:
Sun's Altitude Angle = 40°
Sun's Azimuth Angle = 130° N
The Zenith Angle, defined as the angle between the Sun and the zenith (the point directly overhead), is calculated as follows:
\[{Zenith angle} = 90^\circ - {Altitude angle}\]Substituting the given Altitude Angle of 40°:
\[{Zenith angle} = 90^\circ - 40^\circ = 50^\circ\]Therefore, the Zenith Angle of the Sun at the specified location is 50°.