Hi Anissa S
According to the picture, I see three triangles two Right Triangles and One Obtuse Triangle all of which share the same height. The Obtuse and the Largest Right Triangle share the same Hypotenuse. Below I will define all the Triangles Formed
The Largest Right Triangle contains the following angles 15, 75 and 90 degrees
The Smaller Right Triangle contains the following angles 20, 70 and 90 degrees
The Obtuse Triangle contains the following angles 15, 160, and 5 degrees and also the side opposite the 5 degree angle is 100 ft, the same 100 ft along the base of the largest right triangle. In the Obtuse Triangle has two angles and a non included side.
The Obtuse Triangle and the Largest Right Triangle also share the Hypotenuse
We can use the Law of Sines to calculate the Hypotenuse
100/Sin(5°) = Hypotenuse/sin(160°)
Hypotenuse = 100(sin(160°)/sin(5°)
Hypotenuse = 100*(0.3420)/0.08716 = 392.42
Now that we know Hypotenuse we can calculate the height based on the Largest Right Triangle as follows;
cos 75° = Height/Hypotenuse
cos 75°(Hypotenuse) = Height
0.2588(392.2) = Height
101.566 = Height of the Triangle
Now we need to add Rick's height of 5.5
101.566 + 5.5 = 107.06ft
The height of the Monument is 107 ft
