I don’t get 90-2theta

[thick granite]

18. Set ABCD to be square. There is a point M on the BC side that makes BM =14, a point N on the DC side that makes DN = 9. If AN divides half the MAD angle, what is the area of ABCD square?

[hollow cloak]

!status

[kind wharf]

What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above

[thick granite]

2

[thick granite]

2

[hollow cloak]

May I see your progress?

[thick granite]

This is my progress

[hollow cloak]

uhh, I thought it’s the question

[thick granite]

The image

[hollow cloak]

Ohh

I see

[thick granite]

The image is the progress

It was only the question

[hollow cloak]

Do you know the sum angle formula of tangent?

[thick granite]

The original is in Thai but the translation is accurate

[hollow cloak]

It’s ok

[thick granite]

What’s that

[hollow cloak]

What’s tan 2theta

Do you know how to state it with tan theta?

[thick granite]

Like theta times 2

It’s a square

[hollow cloak]

No, I mean the formula

[thick granite]

What’s that

Im in middle school

[hollow cloak]

It’s the formula of double angle of tangent

Oh I see

[thick granite]

But the questions for high school entrance is above middle school level

[hollow cloak]

No wonder…

[thick granite]

Idk if it’s suppose to be Pythagoras

[hollow cloak]

You’re supposed to acquired crucial tools before approaching this question

[hollow cloak]

This is it

[thick granite]

Is tan 90-2theta = tan 90 - tan 2theta?

[hollow cloak]

No

You can’t deduct degrees like that lol

[thick granite]

How do I use this in my sicuation

[hollow cloak]

There are formulas for those

[hollow cloak]

That formula is derived from the original one

Let me exhibit it rq

[thick granite]

What’s the formula called

[hollow cloak]

Angle sum and difference identities

[thick granite]

This!

[hollow cloak]

Sorry, I was fixing my Internet

[hollow cloak]

You’re supposed to use the last formula

[thick granite]

Bruh

The numbers are getting rediculously big

I think i might be far off track

I found the answer online

Turns out it does use pythagorus

And i was faaaaarrrr off track

Thank you non the less

[thick granite]

6

.close

[kind wharf]

Solved

Post marked as solved by @thick granite.

Use .unsolved if this was a mistake.

[hollow cloak]

LOL, that cannot prove that my idea was infeasible

Whatever

[thick granite]

The numbers were getting huge

I was probs making many algebraic mistakes along the way

[hollow cloak]

Nope, I didn’t encounter "gigantic number" during my process

But still

You’ve solved the problem

[thick granite]

What did you get

[hollow cloak]

So it doesn’t matter anymore

[thick granite]

I found the answer online after hitting a trigomatry roadblock