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.**