Question

7. The stand on a camera can be tilted to a maximum of 15° above the horizontal. If a photographer wants

to take a picture of the top of a 90 ft. building with the camera on the ground, how far back must he place
the camera? Use a half-angle identity to choose the expression that best finds the distance.

Answer 1

D. 90 sin(30°)/1-cos(30°)

Answer 2

Answer: The distance is 335.88 feet away from the building.

Explanation:

Suppose we have a triangle rectangle, where we know that one of the cathetus is equal to 90 ft, the opposite angle to that side is equal to 15° (the maximum angle that the stand can be tilted)

Now we want to know the value of the other cathetus, the adjacent to the angle.

By trigonometry, we know that

Tan(θ) = (opposite cathetus)/(adjacent cathetus)

then:

tg(15°) = 90ft/X

X = 90ft/Tg(15°) = 335.88 ft