Trigonometry
posted by Anonymous .
When viewing Angel Falls (the world's highest waterfall) from Observation Platform A, located on the
same level as the bottom of the waterfall, we calculate the angle of elevation to the top of the waterfall to
be 69.30°. From Observation Platform B, which is located on the same level exactly 1000 feet from the
first observation point, we calculate the angle of elevation to the top of the waterfall to be 52.90°. How
high is the waterfall?

You are obviously looking at or have made a diagram.
let the top of the falls be point C
In triangle ABC
B = 52.9°
A = 110.7° , the supplement of 69.3
then angle C = 16.4°
by the Sine law
AC/sin52.9 = 1000/sin16.4
AC = 2824.8913...
now in the rightangled triangle
sin69.3 = height/2824.8913..
height = 2642.5 feet