Your altitude is 40,000 feet and you detect a target at a depression angle of 6 degrees and a range of 20 miles. what is the altitude of the target? Draw a picture.

2 answers

first you would want to convert feet to miles or vice versa. Then, youll want to build the triangle because you start at 40,000 feet and then that goes at a six degree angle along the x axis for 20 miles. So you will want to put this on a cartesian plane because from there you will want to determine whether you need to use the law of cosines or the law of sines.
ignoring the curvature of the earth, I made a sketch and had the altitude of the target as x feet,
then
sin 6° = (40000-x)/105600
105600 sin6° = 40000 - x
x = 40000 - 105600sin 6° = appr. 28962 feet