# The Numberphile Topic -- The Official Nerdy Math Topic! [OLD]

#413

We have the old math topic by @BuildASnowman, we could use that one.

#414

Hey all! It's a new Goldbachy video!
I mean Numberphile made a new video

#415

Goldbach kinda confuses me xD

#416

Yeah, me too

#417

Can I get a new math problem since I failed my latest xD

@JonnyGamer

#418

Hmm, I'd have to think of one..

#419

Ok.

#420

How long is the unknown side?:

#421

Pythagorean Theorem

16 + 36 = 52
Square root of 52

Can you find the angles!

#422

No I can't.
That's ether sine, cosine or tan.
It's square root of 52 I think

#423

I think it is 7.21110255093 or rather the square root of 52

16+36=52, not 42!

#424

Oops! I was off by 10!

#425

The things that math teachers put on homeworks...
Like, really!
If 3m=5a, and m-a=80, what is the value of m?

I could go on and start to rant, but, I'll save you guys and won't...math is too easy for me..

#426

I have a math question that is kind of hard-ish if you haven't ever heard of 3d plane figures before in graphing. Below there are three simultaneous equations. Solve for x, y and z. Then graph the equations on an xyz grid.

3x+2y-3z=2
-x+4y-3=2z
-2x-y+2z=0

#427

I am trying to find out the angles of a triangle based on the lengths of the sides. I found this:

Let △ABC have sides a, b, and c.
We are using the usual convention that the length of the side
opposite vertex A is called a, and so on.

Let θ=∠C. Then the Cosine Law says that

c^2 = a^2 + b^2 − 2ab cosθ`

So how do you reverse this to get θ?

#428

Oooh that is a very great question.

...can I suggest an idea? Looks like θ is a variable in that equation, like x or y might be.

#429

May I get a math problem?

#430

Sure. Do you want an algebraic one?

#431

Okay

#432

Hmm, I'll give you the same one I posted before.

Solve for x, y, and z.