Step 1: Read the question and make a note of the important points

              NOTE: Angle of elevation is the angle between observer's eye(horizontal

      line of reference) and top of object at observer's line of sight (tree in this case).

            Height of tree = y = 12.7 m

            Horizontal Distance between point of observation and object= x = 23.7 m

           Angle of elevation = \theta = ?

Step 2: Find the suitable trigonometric ratio to calculate angle of elevation

             NOTE: Consider a right angled triangle formed with vertical side as height

             of tree (y) and horizontal side as observation distance (x). Angle θ is the

             acute angle formed which can be found using trigonometric function i.e.

             \tan \theta .

            Solution:

                   \tan \theta = \frac{opposite}{adjacent}

                   \tan \theta = \frac{y}{x}

                   \tan \theta = \frac{12.7}{23.7}

                   \tan \theta = 0.5358

                   \theta = \tan^{-1}(0.5358)

                   \theta = 28.1824

              Therefore angle of elevation = \theta = 28.1824