SOLUTION: A commercial airline is flying at 10km from the ground. It it approches the landing at an angle of 5 degrees from the ground, at what distance should the airplane begin it's descen

Algebra ->  Trigonometry-basics -> SOLUTION: A commercial airline is flying at 10km from the ground. It it approches the landing at an angle of 5 degrees from the ground, at what distance should the airplane begin it's descen      Log On


   

Question 106690: A commercial airline is flying at 10km from the ground. It it approches the landing at an angle of 5 degrees from the ground, at what distance should the airplane begin it's descent? (answer is 114km from the airport, but need to know how to get there)
Found 2 solutions by rcmcc, edjones:
Answer by rcmcc(152) About Me  (Show Source):
You can put this solution on YOUR website!
To solve this question you are looking for the base of a right angle triangle.
you are given the opposite side of the triangle (10km)
and are looking for the adj side of the triangle to 5 degrees
because you are using the opp and adj sides of the triangle you use your trig functions. knowing tangent uses opp and adj sides you can make an equation
tan%285%29=%2810%2Fadj%29
we are given the opposite side of 10 and are looking for the adj side. to find the adj side you use the cross mulitplication rules to rearrange the equation
so
adj=%2810%2Ftan%285%29%29
if your calculator is in degree mode you will get the answer 114.3km
Good Luck

Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
Construc a right triangle with hight 10 and angle opposite the height of 5 deg.
You need to know the length of the line adjacent to the angle (running along the ground).
cot=adj/opp
cot(5)=a/10
a=cot(5)*10
a=114.301 km
Ed