15. A math teacher at Vallivue High School measured the angle of elevation from the ground to the flag at
the top of the school’s flagpole. She took the measurement from the ground 25 feet away from the
flagpole, and found that it was a 50 ◦ angle of elevation. When the flag was lowered to half-staff, she
found the angle decreased by 18 ◦. How much was the flag lowered, in feet? Draw a diagram to
support your answer.
The diagram is given below.
In diagram, A is the flag position, C is the point where the flag is lowered.
by using trigonometry,
Thus, the flag lowered by 14.17 ft.