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-   -   trig question - help me find X (http://www.risingsun4x4club.org/forum2/showthread.php?t=12557)

nakman 03-19-2010 10:11 PM

trig question - help me find X
 
1 Attachment(s)
I am trying to draw out the bolt pattern of a 6 on 5.5 wheel spacer.. and my limited CAD ability has revealed a very rusty trig ability. When I was 16 I could have done this on a napkin in about 2 minutes... but tonight I find myself scratching my head.. :o

Can someone solve this? 30-60-90 triangle, the long leg that's not the hypotenuse is 2.25, aka the radius of the 5.5" circle. I need to know how far "up" or down, or sideways to draw, so that I can draw in the hypotenuse then create a lug hole where that intersects the circle. Here's a chance to prove how smart you is.. what's X? :confused:

wesintl 03-19-2010 10:20 PM

1 * √2.25 ? I need to find the trig and geometry symbols but i think you will know what i'm talking about

AxleIke 03-19-2010 10:21 PM

Sure thing:

Tan 30 = x/2.250

.5773 = x/ 2.25

x= 1.299"

fubuki 03-19-2010 10:23 PM

http://www.thealarmclock.com/euro/images/findX.gif

AxleIke 03-19-2010 10:26 PM

An easy way to remember these trig functions is the following pnuemonic:

Chief SOH CAH TOA (pronounced Cheif soak-a toe-a)

The SOH CAH TOA part is as follows

SINE = OPPOSITE over HYPOTENUSE

COSINE = ADJACENT over HYPOTENUSE

TANGENT = OPPOSITE over ADJACENT

Where the hypotenuse is obvious, and the adjacent side is not the hypotenuse, but the other connecting side to the angle you have, and the opposite is the one not touching the angle, if that makes any sense.

nakman 03-19-2010 10:32 PM

1 Attachment(s)
Quote:

Originally Posted by AxleIke (Post 143133)
Sure thing:

Tan 30 = x/2.250

.5773 = x/ 2.25

x= 1.299"

Dr. Axle, thanks man! :bowdown:


edit: yeah I remember the SOH CAH TOA from high school, just couldn't seem to get it, and using the computer calculator probably didn't help me either. I remembered the sin of a 30 degree angle was .5, yet for some reason my answer wasn't double or half of my known value. I can't wait until Gavin learns this stuff, so I can learn it all over again. :)

wesintl 03-19-2010 10:37 PM

Doh.. I think i was in the ball park.. lol

can the airplane take off on that triangle Tim?

nakman 03-19-2010 10:40 PM

Quote:

Originally Posted by wesintl (Post 143141)

can the airplane take off on that triangle Tim?

Only if the hypotenuse is a conveyor belt. :D



edit: and good one Fubuki, was hoping someone would post that one. :)

rover67 03-19-2010 10:40 PM

Isaac is right but I think you are looking for a different number... since the lugs on that pattern are 60* apart it's Tan (60) = x / 2.25

so:

x = 3.897

Edit: Nevermind, you two confused me. Don't look at these numbers. :D

nakman 03-19-2010 10:51 PM

1 Attachment(s)
Quote:

Originally Posted by rover67 (Post 143143)
Isaac is right but I think you are looking for a different number... since the lugs on that pattern are 60* apart it's Tan (60) = x / 2.25

so:

x = 3.897

Edit: Nevermind, you two confused me. Don't look at these numbers. :D

dude you're cracking me up..

but hey i drew a wheel spacer!


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