Two birds sit at the top of two different trees 17.8 feet away from one another. The distance between the first bird and a bird watcher on the ground is 37.4 feet.

What is the angle measure, or angle of depression, between this bird and the bird watcher?

25.5°

64.5°

28.4°

61.6°

Question

Two birds sit at the top of two different trees 17.8 feet away from one another. The distance between the first bird and a bird watcher on the ground is 37.4 feet. 

What is the angle measure, or angle of depression, between this bird and the bird watcher?

25.5°

 64.5°

 28.4°

 61.6°

anonymous · Answer

attachment

anonymous · Answer

Please help !

jdoe0001 · Answer

are those birds eating cherries?

jdoe0001 · Answer

would you say that the 37.4 side is the hypotenuse of the angle "x"?

anonymous · Answer

Yes, I think

jdoe0001 · Answer

well, so if that's the hypotenuse, what side is the 17.8 one, the opposite side or the adjacent side to angle "x"?

jdoe0001 · Answer

lemme flip the angle upside down|dw:1379007807609:dw|

anonymous · Answer

17.8 is the adjacent side?

jdoe0001 · Answer

so we have 2 sides, the hypotenuse and the adjacent side
so what trigonometric identity uses those 2 only?   I assume you have a trig identities sheet

anonymous · Answer

Is it tan?

jdoe0001 · Answer

http://www.mathwarehouse.com/trigonometry/images/sohcohtoa/sohcahtoa-all.png <--- notice, tangent uses opposite/adjacent we don't have opposite, just adjacent and hypotenuse

anonymous · Answer

Oh i see. So cos

jdoe0001 · Answer

that means that $\bf cos(x) = \cfrac{adjacent}{hypotenuse} \implies cos(x) =\cfrac{17.8}{37.4}\ \implies cos^{-1}(cos(x)) = cos^{-1}\left(\cfrac{17.8}{37.4}\right)\ \quad \
x = cos^{-1}\left(\cfrac{17.8}{37.4}\right)$

jdoe0001 · Answer

they want degrees for the angle, thus when taking the inverse cosine of that, make sure your calculator is in Degrees Mode

anonymous · Answer

I got .25 ??

jdoe0001 · Answer

yes, that means your calculator is in Radians mode
that'd mean 0.25 RADIANS maybe

is actually a bit more than 1 radian btw

anyhow, make sure your calculator is in Degrees mode
is more than that :)

anonymous · Answer

what is it in degrees because i can't figure it out

jdoe0001 · Answer

hmmm, what did you get for $\bf \cfrac{17.8}{37.4} \quad ?$

anonymous · Answer

.47

jdoe0001 · Answer

so, if you put 0.47 in your calculator, and the press .... let's check in google's calculator :) https://www.google.com/search?client=opera&rls=en&q=arccosine+of+(17.8/37.4)&sourceid=opera&ie=utf-8&oe=utf-8&channel=suggest#channel=suggest&q=arccos+of+(17.8%2F37.4)+in+degrees&rls=en

anonymous · Answer

Ohh, thanks for helping

jdoe0001 · Answer

yw