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"Maths Problem"

Really stuck on maths, can somone help please?

In triangle KLM, angle LKM = 45degrees and angle LMK = 30degrees. Find the exact value of LM/KL.

I managed to convince myself it was done with the cosine rule.

And, umm, watch out for the typo in the very last line :)

And if you studied the Sine Formula recently, then you know this method is the right one to use. If you've never studied the Sine Formula, then it's probably wrong :)

Sdrawkcab wrote:
> Really stuck on maths, can somone help please?
>
> In triangle KLM, angle LKM = 45degrees and angle LMK = 30degrees. Find
> the exact value of LM/KL.

From your info you know that

Angle M = 30 degrees
Angle K = 45 degrees
Therefore:
Angle L = 105 degrees (180 degrees in a triangle)

***The Sine Formula*** for general triangles shows that:

a/Sin A = b/Sin B = c/Sin c

or in our case:

LM/Sin K = KL/Sin M = MK/Sin L

Substituting known values you then have:

LM/Sin 45 = KL/Sin 30

This can simplify to

LM/KL = Sin 45/Sin 30 = 1.414213562

Therefore LM/KL = 1.141213562 to 9 d.p.

only way i can think of doing it is by drawing a triangle with those angles and then working it out from the measurements you have.

You will always get the same anser no matter how big/small your triangle is.


I would do it for you but i havnt got a clue where my protacter is from my maths a-level days.

Got to go. Let me know, yeah?

Bah humbug, French beckons. Keep trying, I'll re-check at about 8 tomorrow morning.

Keep trying! Rack your brains!

phi11ip wrote:
> A triangle
>
> AngleA = 90 degrees
> AngleB = 90 degrees
>
> What is angleC?

46.08307578458648560450258704570457 (deep breath) 1345995608007526702976 degrees. Or not.

But getting back to the point, how the hell do you do this maths?

phi11ip wrote:
> A triangle
>
> AngleA = 90 degrees
> AngleB = 90 degrees
>
> What is angleC?

That ain't a triangle, that would end up with a pair of paralell lines.