Point A is between point B and C, the distances of point B and C from point A are 1km and 2 km respectively. Measured from point A, the angle of elevation of point B is 1813’ while that of C is...

Point A is between point B
and C, the distances of point B and C from
point A are 1km and 2 km respectively.
Measured from point A, the angle of
elevation of point B is 1813’ while that of C
is theta. The difference in the elevation of B and
C is 44.4 m. Considering the effects of
curvature and refraction. What is the value
of theta?