In the figure, $\varphi$ represents the angle subtended by a 5 ft picture when viewed from point P that is 7 ft below the picture and 14 ft away from the wall on which the picture hangs.

In the figure, $\varphi$ represents the angle subtended by a 5 ft picture when viewed from point P that is 7 ft below the picture and 14 ft away from the wall on which the picture hangs. Solve for $\varphi$ and express the answer using the arctan notation.

basic_019-sum-of-two-angles.gif

 

At a point A that is 50 m from the base of a monument, the angle of elevation to the top of the monument is twice as large as the angle of elevation from a point B that is 150 m from the monument.

At a point A that is 50 m from the base of a monument, the angle of elevation to the top of the monument is twice as large as the angle of elevation from a point B that is 150 m from the monument. Assuming that the base of the monument and the points A and B are in the same line on level ground, find the height of the monument.