Answer: option A. 30 °.
Explanation:
1) Draw this triangle: Eyes - Ship A - height of the cliff:
The angle of the vertix where the eyes are is: 90° - depreesion angle = 90° - 60° = 30°.
2) opossite leg = horizontal distance to the ship A = x
3) adjacent leg = height of the cliff = 1500 feet
4) tan(30°) = x / 1500 feet => x = 1500 tan(30°) = 1500 √3 / 3 = 500√3
5) Draw the triangle of the eyes - ship B - hieght of the cliff
6) The unknown is the depression angle of the eyes with ship B, α
7) opposite leg = 500√3 feet + 1000√3 feet = 1500√3 feet
8) adjacent leg = height of the cliff = 1500 feet
9) tan(α) = opposite leg / adjacent leg = 1500√3 / 1500 = √3
10) α = arctan(√3) = 60°
11) Depression angle = 90° - 60° = 30° Which is the answer
Since CB || ED and CB = ED,
by the alternate interior angles theorem,
mE = mC, and mD = mB.
with CB = ED, we can conclude that CBF = EDF, by SAS congruent theorem.
It’s the third one ............
