in order to land safely, a helicopter needs to know how high it is from a helipad, how far horizontally it is from the helipad, how far is it to fly (diagonally), as well as the angle of depression. A helicopter wants to land on a hospital helipad that is 2 miles away (horizontally), and wants to start its (diagonal) descent. If the angle of depression to the helipad is 38°, what is the helicopter's altitude?

Question

pawanyadav · Answer

Hint: tanx=perpendicular/base

pawanyadav · Answer

Perpendicular means altitude

lokiando · Answer

I don't know if "a" is right

mathmale · Answer

Looks good.  You correctly show that the horiz. distance is 2 miles and that the angle of depression is 38 degrees.  Now, which trig function will you use the calculate the height of the helicopter off its pad?

lokiando · Answer

not sure, the hypotenuse suppose to be at the bottom?

mathmale · Answer

Ask yourself:  Which side of this right triangle is the longest?  That's your hyp.

lokiando · Answer

yea, its the diagonal angle

mathmale · Answer

The figure features 2 sides and the hyp. (longest side).  Which of the 2 sides is unknown?  What's its name, given that it's opposite the 38 deg angle?

mathmale · Answer

What's the name of the side of known length?

lokiando · Answer

Like this?

mathmale · Answer

that's great!  Now, given that you want to find the length of the vertical side (the opp side), and that you know the angle 38 deg and the length of the adj. side, which trig function will most quickly let you calculate the unknown?