#Geometry thales theorem

224 messages · Page 1 of 1 (latest)

gleaming ravenBOT
proven trench
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How do i solve ex

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4

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Part A

tropic beacon
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Hi

proven trench
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Hi

tropic beacon
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Do u see that OF = OE?

proven trench
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Yes

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Radii in same circle

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They're both 3 cm

tropic beacon
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So it comes to proving OA=OI

tropic beacon
proven trench
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OI is 5cm

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OOOOOHOOOO

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Now i knowit

tropic beacon
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Great

proven trench
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Since EF//AI

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So we can apple thales

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So

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Apply*

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Then:

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OF/OI=OE/OA

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Now we replace

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3/OI=3/5

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Now

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3x5/3=OI

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So

tropic beacon
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Yuss

proven trench
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OI=5

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Tysm

tropic beacon
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Congrats

tropic beacon
proven trench
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U showed me how to think

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I didnt know where to start

tropic beacon
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Ur welcome if

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Ig

proven trench
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Ty

tropic beacon
proven trench
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@tropic beacon

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Pls help again

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In number 5 a

tropic beacon
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U see how AFO is a right angle

proven trench
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Yes

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OOOOH

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So that means

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FI is a diameters

tropic beacon
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What

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No

proven trench
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And same with FEI

tropic beacon
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FI isn't diameter

proven trench
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I mean in C'

tropic beacon
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?

proven trench
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Read question again

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They want in circle C'

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Oh wait

tropic beacon
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No. OA is 5, OF is 3, so by pythagoras, AF is 4

proven trench
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AI is diameter

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Not FI

tropic beacon
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What

proven trench
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Yes bro

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Because

tropic beacon
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BE is diameter

proven trench
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I mean in circle C'

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Yes i know its not drawn

tropic beacon
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Ahhh

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Ok

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Yes

proven trench
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But we have to imagine it

tropic beacon
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But u need not use that for verifying AF=4

proven trench
tropic beacon
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U just wanna find AF right?

proven trench
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Nooooo

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I said question 5 a

tropic beacon
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Ohh

proven trench
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Not b

tropic beacon
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Oh I saw b

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Wait

proven trench
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Its ok

tropic beacon
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Ok that's easy

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AFO and AEI are right angles

proven trench
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Is it like i said diameter??

tropic beacon
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U know how two lines from end point of diameter to the circumference make a right angle?

proven trench
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Yes

tropic beacon
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So u can assume AI to be diameter

proven trench
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Yes

tropic beacon
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Yes

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U got it

proven trench
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But how are they on same circle

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Oh wait

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Nvm

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Ok

tropic beacon
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Yes

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Nice

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U can solve bro

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Good luck

proven trench
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And then we find AF with Pythagoras

tropic beacon
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Yes

proven trench
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Like u said

tropic beacon
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Yea

proven trench
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And in 5C

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Diameter

tropic beacon
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No wait

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Sorry

proven trench
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Is AI

tropic beacon
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Wait

proven trench
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What

tropic beacon
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We haven't yet verifed

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Why it has to be

proven trench
tropic beacon
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On a circle

proven trench
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Oh

tropic beacon
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Frankly idk

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Someone else might help

proven trench
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Isnt it because

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AI is diameter and F is a point on circle

tropic beacon
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Ive done this stuff like 4 years ago

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Never touched again

proven trench
tropic beacon
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_<

proven trench
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Its ok i knew it

tropic beacon
proven trench
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But how

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Wiat u can do one thing

proven trench
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Since the anglea are right

tropic beacon
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Construct a mid point M of AI

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Oh wait yes

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Ok maybe what i said earlier was right

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If its right angle

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It has to lie on the circle with AI diameter

proven trench
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Yrs

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Yes

tropic beacon
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But I think it's better if u

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Verify with someone else

proven trench
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Ok

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Cuz I'm too rusty with this studf

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Hello Rusty, Im Dad

proven trench
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And 5 c is

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Because

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AI is diameter

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Umm

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We use Pythagoras

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So

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AF2 + FI2= AI2

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So

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Wait what

tropic beacon
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Is the Triangle Right Angled tho?

proven trench
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Yes

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How do we solve 5 b

tropic beacon
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Give me a sec

proven trench
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Ok

tropic beacon
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Pythagoras

proven trench
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But we dont have AI

tropic beacon
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AO^2= AF^2+OF^2

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Still a right angle Triangle

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All good?

proven trench
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We dont have AO

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Oh nvm

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Its 5

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Ok so then

tropic beacon
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.-.

proven trench
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25=af2 +9

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AF2=-25+9

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What

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How

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-AF^2=-25+9

proven trench
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Man math aint mathing

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Oh

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Yes

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-AF2=-16

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AF2=16

tropic beacon
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4

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AF=4

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Ok

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K

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Now

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We find AI

tropic beacon
proven trench
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man we dont have FI

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Ohhh

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FO+OI

proven trench
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We dont have OI

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Oh wait

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We use thales theorem

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4 b)????

proven trench
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wdym

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We found AF

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Its 4

tropic beacon
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You already t
Found OI at 4.b)

tropic beacon
proven trench
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Oh

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So

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Its

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8

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So

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AI2=64+16

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AI2=80

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AI=square root 80

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$4 \sqrt(5)$

weary roostBOT
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I have No User Name but I must

proven trench
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Yes

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But wait

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...

proven trench
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There was another way

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Faster way

tropic beacon
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Ok...

proven trench
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Using thales theorem

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I'm gonna leave

proven trench
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Since OF/OI=OE/OA=FE/AI

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Then

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We replace values

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3/5=3/5=FE/AI

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Now

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Hmmm

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Nvm

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It wont work