Projectile Motion Problems- Find Angle

[312213]

Homework Statement

(e) What is the angle made by the velocity vector with the horizontal?

A projectile is shot from the edge of a cliff h = 165 m above ground level with an initial speed of v0 = 145 m/s at an angle of 37.0° with the horizontal, as shown below:
http://img135.imageshack.us/img135/3468/projectilelaunchox5.th.jpg http://g.imageshack.us/thpix.php

Seconds in the air is 19.532760239244074174748994000901s
Range of total distance traveled is 2261.9356107635250879761691838034m
Final Velocity for x before it hits the ground: 115.80214895685746271118011659m/s
Final Velocity for y before it hits the ground: -104.15787198754492632443347614472m/s (upwards is positive)
Magnitude of final velocities (hypotenuse-more or less): 155.75300960174092250733936761367m/s

These are just other informations obtained throughout the problem.

Homework Equations

Trigonometry-sin/cos/tan

The Attempt at a Solution

Basically I used opposite divided by adjacent and then inverse tan it.
Tan θ = opp/adj
Tan θ = 165m/2261.9356107635250879761691838034m
θ = 4.172129598188136156302219438937°
Here is a picture of it, very slightly modified:
[img=http://img583.imageshack.us/img583/733/projectilelaunchangleik5.th.jpg] (the picture won't show up as image)

This did not come out as correct. If anyone can point out errors to find the correct answer, it would be appreciated.

 

[Mentallic]

All those decimal places make it quite hard to follow (just a tip, if you want very precise answers, use the exact answer rather than a string of decimals) but the only mistake you made that I can quickly spot out is that you used

tan\theta=(vertical displacement) / (horizontal displacement)

rather you need to use the tangent for the horizontal and vertical velocity vectors to find the angle it makes with the horizontal.

 

[312213]

Thanks. That was correct. I see what I did wrong. Thank you.