trig help! (1 Viewer)

[tooheyz]

hey guys... if you could help me with this darn trig question it would be much appreciated!

its been buggin me for a while!

an observer notes that the wing span of an areoplane directly overhead subtends an angle of 20 minutes at his eye. if the wing span is known to be 30 meters, find the height of the areoplane to the nearest 100m.

answer is 5200m

thanks in advance

 

[Jinglebell]

this is fairly straightforward trig, especially if you can get a diagram. i can't draw it here, but if you draw a right-angled triangle with the top parallel to the top of the page, the top side will be 30m, the vertical side will be x and the bottom angle (adj. to x) will be 20'.

from this, we can see that:

tan 20' = 30/x
therefore x = 30/tan 20'
= 5156.562.....

...which rounds to 5200m

simple once you figure how it's done

 

[tooheyz]

oh my god! man its soOoO simple... far out..

the reason why i got it so wrong was coz my diagram looked something like this...

/|

instead of \|

if you could see what i mean... because i got the diagram wrong i got the angle wrong... ppppsssft.

thanks dude! your a legend!

 

[Jinglebell]

yeah, i did the same thing at first, then i thought "wait a sec, what if..." and tried it the other way. the wording of the q made it a bit hard to figure which way to do the diagram, i reckon.

 

[lizzy1004]

if we r gonna han heaps of those questions l'm soooooo dead... i hate those word problems d most... i just cant draw d diagram da right way!

 

[tooheyz]

yeah i know... drawing the diagram is a hard thing... i guess its the way ya interepret the question.. make sure u read it right and pick out everys ingle detail.. the more u practice the better u'll get