To solve, refer to the figure below.
In the figure, `theta` is the angle of elevation of the sun. To determine its value, use the tangent function since the length of the sides opposite and adjacent to theta are known.
`tan theta=(opposite)/(adjacent )`
`tan theta=15/20`
`tan theta=3/4`
`theta=tan^(-1)3/4`
`theta=36.86989764^o`
Rounding off to the nearest degree, it becomes:
`theta=37^o`
Hence, the angle of elevation of the sun is 37 degrees.