Too hard but easy

Geometry Level 4

Find measure of angle x x , that is angle B F E BFE .


The answer is 30.

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4 solutions

Ahmad Saad
Feb 15, 2016

You took a screenshot of the Vedio, didn't you? Here is the link of the Vedio I am talking about https://m.youtube.com/watch?v=e_fMujlRiTE

Rishabh Sood - 5 years, 4 months ago

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Yeah,bro I had a major doubt on that

Rishabh Sood - 5 years, 3 months ago

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Major Rishabh Sood?

Ashish Menon - 5 years, 3 months ago

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@Ashish Menon Yes sir a very major doubt

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood I have explained your doubt for my question squaring it.

Ashish Menon - 5 years, 3 months ago

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@Ashish Menon Can you please stop blowing me away? You won't see me on the earth next time I am telling you

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood Lol ,just joking nice solution

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood Lol, okok I would post an easier question next time.

Ashish Menon - 5 years, 3 months ago

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@Ashish Menon Tell me one thing, you love in India right?

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood Sorry, I meant live

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood Yes I do. But i have studied from class kg1 to 5 in dubai. Then after coming here, i greatly enhanced in maths.

Ashish Menon - 5 years, 3 months ago

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@Ashish Menon Hmm, which state ? I mean like somewhere in Northampton? I live in noida

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood Sorry I meant north, this keyboard is shit

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood Noida is in UP

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood Okok, bye have to go to eat

Ashish Menon - 5 years, 3 months ago

@Rishabh Sood Ok, i am from south , but live in west.

Ashish Menon - 5 years, 3 months ago

@Rishabh Sood Wt?.. I am from kerala and i live in gujarat wt is noida

Ashish Menon - 5 years, 3 months ago

If you did not, then good effort bro! Keep it up

Rishabh Sood - 5 years, 4 months ago

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Really, i do not think that he really made an effort.Maybe. but i have a 75% belief that he viewed the video.

Ashish Menon - 5 years, 4 months ago

Though not clear, I assume FBC as 60.
L e t O = E C F B . C E B = 50 , E B = B C . C O B = 70 , F E C = 110 X . C F B = 40. Let \color{#3D99F6}{O=EC\cap FB.~~~\angle CEB=50, ~\therefore~EB=BC}.\\ \angle ~COB=70 , ~ \therefore~ FEC=110 - X. ~\angle ~CFB=40.\\ A p p l y i n g S i n L a w , w e h a v e : I n Δ E B C , F C E B = F C B C = S i n 60 S i n 40 . Applying ~ Sin ~ Law, ~we ~have:-\\ In ~\Delta ~EBC, ~\dfrac{FC}{EB}=\dfrac{FC}{BC} =\dfrac{Sin60}{Sin40}.\\

I n Δ s F E C a n d F E C , F E = S i n 20 E B S i n X = S i n 30 F C S i n ( 110 X ) . C o l l e c t i n g a n d e x p a n d i n g S i n ( 110 X ) , S i n 110 C o t X C o s 110 = S i n 30 S i n 20 F C E B = S i n 30 S i n 20 S i n 60 S i n 40 . S o l v i n g , X = 3 0 o . In ~\Delta s ~FEC ~and ~ FEC, FE=Sin20*\dfrac{EB}{SinX}=Sin30*\dfrac{FC}{Sin(110 - X)}.\\ Collecting ~ and ~expanding ~Sin(110 - X),\\ Sin110*CotX - Cos110 = \dfrac{Sin30}{Sin20}*\dfrac{FC}{EB}=\dfrac{Sin30}{Sin20}*\dfrac{Sin60}{Sin40}.\\ Solving,~~X=30^o.

Good, but I meant this question to be solved by only using elementary geometry

Rishabh Sood - 5 years, 3 months ago

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Is this question original?

Anik Mandal - 5 years, 3 months ago

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No, God came to me and blessed me with it. Pretty dumb no? That's what your question sounds like! Do not try to insult my question by posting such comments s!

Rishabh Sood - 5 years, 3 months ago

If you want to watch video on it watch it here

Thank you Rishabh, Sincerely from Rishabh (Now figure out which one is which!😂)

Rishabh Sood - 5 years, 2 months ago
Ashish Menon
Feb 15, 2016

Now, everyone solves a question in the traditional way.
NOW, READING THE SOLUTION I HAVE POSTED PLEASE DO NOT C R Y CRY W I T H WITH L A U G H T E R LAUGHTER .
I C o n s t r u c t e d Constructed the diagram.

Dude...., lol

Rishabh Sood - 5 years, 4 months ago

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Try calculator ' s worst enemy, my latest problem. Now I would be posting questions only after my b o a r d board e x a m exam

Ashish Menon - 5 years, 4 months ago

Hahaha, I figured it out traditionally only after constructing it.

Ashish Menon - 5 years, 4 months ago

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Yeah good old traditional methods

Rishabh Sood - 5 years, 4 months ago

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@Rishabh Sood Agreed. Did you try Calculator ' s worst enemy. Seeing my question, my brother looked like 《○¤¤○》

Ashish Menon - 5 years, 4 months ago

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@Ashish Menon Done, it will be the square of 1/2*32 that is largest 16 digit number, 9999999....... So, the answer will the square of 9999999999999999

Rishabh Sood - 5 years, 4 months ago

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@Rishabh Sood U got me. Did u write the answer. Or did u get bored typing the answer. Lol. It is very very very very very very very very very very very big answer

Ashish Menon - 5 years, 4 months ago

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@Ashish Menon I know, you know how lazy I am. So didn't care posting a solution. Yours is good enough to understand

Rishabh Sood - 5 years, 4 months ago

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@Rishabh Sood Nice set by the way, Thanks for including all my problems

Rishabh Sood - 5 years, 4 months ago

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@Rishabh Sood Okok, try my last question before board exam "squaring it". And i dont think that you are lazy.

Ashish Menon - 5 years, 4 months ago

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@Ashish Menon Try ugly polygon too

Ashish Menon - 5 years, 3 months ago

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@Ashish Menon Ok, so tell me really which is your real last question before the board exams?

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood Really, i dont know. My exams are on 29 feb. And it is no oedinary one, it is the board exam. But i am addicted to brilliant.

Ashish Menon - 5 years, 3 months ago

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@Ashish Menon Who isn't?

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood Who are not members of brilliant

Ashish Menon - 5 years, 3 months ago

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@Ashish Menon Ohhhhhhhhh, 🙏🙏🙏🙏🙏👍

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood Hmmm, i have to stidy hard for exams. So is said by my parents. But i know that I have finished it.

Ashish Menon - 5 years, 3 months ago

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@Ashish Menon It's almost always the similar case with me

Rishabh Sood - 5 years, 3 months ago

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@Rishabh Sood Whose is not

Ashish Menon - 5 years, 3 months ago

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