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## #1 2017-03-18 02:52:19

!nval!d_us3rnam3
Member
From: Mind ur own beeswax XD
Registered: 2017-03-18
Posts: 13

### Help me; need answer before tonight. Thanks!

Let the incircle of triangle $ABC$ be tangent to sides $\overline{BC}$, $\overline{AC}$, and $\overline{AB}$ at $D$, $E$, and $F$, respectively. Prove that triangle $DEF$ is acute.

I have tried proving that triangle DEF's angles were less than the opposite angles in triangle ABC, but that wasn't really complete. Can anyone help? Thanks!

Clean Clash Royale Jokes
Newb: I'm only arena 4 and I have a level 7 goblin barrel! Pro: How?
Newb: The goblins it spawns are level 7! Pro:

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## #2 2017-03-18 05:42:32

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,496

### Re: Help me; need answer before tonight. Thanks!

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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## #3 2017-03-18 09:03:01

!nval!d_us3rnam3
Member
From: Mind ur own beeswax XD
Registered: 2017-03-18
Posts: 13

### Re: Help me; need answer before tonight. Thanks!

Thank you so much for helping!

Clean Clash Royale Jokes
Newb: I'm only arena 4 and I have a level 7 goblin barrel! Pro: How?
Newb: The goblins it spawns are level 7! Pro:

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## #4 2017-03-18 11:05:07

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,496

### Re: Help me; need answer before tonight. Thanks!

Hi;

Hopefully, it will inspire you to learn more math and spread that to others. Welcome to the forum.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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