Angle oriented geometry

by Problems_eater, Apr 15, 2025, 9:03 PM

Let $A, B, C,D$ be four distinct points in the plane.
Which of the following statements, expressed using oriented angles, are always true?

1.If lines $AB$ and $CD$ are distinct and parallel, then
the oriented angle $ABC$ is equal to the oriented angle DCB.

2.If $B$ lies on the segment $AC$, then
the oriented angle $DBA$ plus the oriented angle $DBC $equals $180°$.

3.If the oriented angle$ ABC$ plus the oriented angle $BCD$ equals 0°, then
lines $AB $and $CD$ are parallel.

4.If the oriented angle $ABC$ plus the oriented angle $BCD$ equals $180°$, then
lines $AB$ and $CD$are parallel.

purple comet math competition question

by AVY2024, Apr 15, 2025, 11:00 AM

Given that (1 + tan 1)(1 + tan 2). . .(1 + tan 45) = 2n, find n

Combination

by aria123, Apr 15, 2025, 10:59 AM

Prove that three squares of side length $4$ cannot completely cover a square of side length $5$, if the three smaller squares do not overlap in their interiors (i.e., they may touch at edges or corners, but no part of one lies over another).

Inequalities

by sqing, Apr 15, 2025, 8:59 AM

Let $   a,b    $ be reals such that $  a^2-ab+b^2 =3$ . Prove that
$$  \frac{13}{ 10 }> \frac{1}{ a^2+1 }+ \frac{1}{ b^2+1 } \geq \frac{1}{ 2 }$$$$   \frac{6}{ 5 }>\frac{1}{ a^4+1 }+ \frac{1}{ b^4+1 } \geq   \frac{1}{ 5 }$$$$  \frac{1}{ a^6+1 }+ \frac{1}{ b^6+1 } \geq   \frac{1}{ 14 }$$

Polynomials

by CuriousBabu, Apr 14, 2025, 4:09 PM

how many quadrilaterals ?

by Ecrin_eren, Apr 13, 2025, 4:01 PM

"All the diagonals of an 11-gon are drawn. How many quadrilaterals can be formed using these diagonals as sides? (The vertices of the quadrilaterals are selected from the vertices of the 11-gon.)"

Plane geometry problem with inequalities

by ReticulatedPython, Apr 10, 2025, 3:59 PM

Let $A$ and $B$ be points on a plane such that $AB=1.$ Let $P$ be a point on that plane such that $$\frac{AP^2+BP^2}{(AP)(BP)}=3.$$Prove that $$AP \in \left[\frac{5-\sqrt{5}}{10}, \frac{-1+\sqrt{5}}{2}\right] \cup \left[\frac{5+\sqrt{5}}{10}, \frac{1+\sqrt{5}}{2}\right].$$
Source: Own
This post has been edited 5 times. Last edited by ReticulatedPython, Apr 10, 2025, 4:42 PM

idk12345678 Math Contest

by idk12345678, Apr 10, 2025, 2:34 PM

Welcome to the 1st idk12345678 Math Contest.
You have 4 hours. You do not have to prove your answers.
Post \signup username to sign up. Post your answers in a hide tag and I will tell you your score.*


The contest is attached to the post

Clarifications

*I mightve done them wrong feel free to ask about an answer
Attachments:
contest.pdf (26kb)

Geo Mock #6

by Bluesoul, Apr 1, 2025, 7:04 AM

Consider triangle $ABC$ with $AB=5, BC=8, AC=7$, denote the incenter of the triangle as $I$. Extend $BI$ to meet the circumcircle of $\triangle{AIC}$ at $Q\neq I$, find the length of $QC$.
L

Inequalities

by sqing, Dec 3, 2024, 11:19 AM

Let $ a,b,c,d>0 $ and $(a+c)(b+d)=ac+\frac{3}{2}bd.$ Prove that
$$\frac{a}{b}+\frac{b}{c}+\frac{c}{d}+\frac{d}{a}\geq \frac{20-\sqrt{10}}{3}$$Let $ a,b,c,d>0 $ and $(a+c)(b+d)=ac+\frac{4}{3}bd.$ Prove that
$$\frac{a}{b}+\frac{b}{c}+\frac{c}{d}+\frac{d}{a}\geq \frac{21-\sqrt{6}}{3}$$

"Where wisdom and valor fail, all that remains is faith. . . And it can overcome all." -Toa Mata Tahu

avatar

EpicSkills32
Archives
+ June 2023
+ February 2023
+ July 2020
+ November 2018
+ October 2018
+ September 2017
+ August 2017
+ July 2017
+ December 2016
+ July 2016
+ May 2016
+ February 2016
+ December 2015
+ June 2015
+ July 2013
ATI
Shouts
Submit
  • The most viewed blog of all time

    by giangtruong13, Feb 24, 2025, 1:37 PM

  • wow this blog is ancient
    it started when I was an infant
    wow and like 1.5 million views

    by nmlikesmath, Oct 13, 2024, 10:09 PM

  • no ur cool

    tbh it scares me too I still dont know where those views came from

    by EpicSkills32, Oct 5, 2024, 9:44 AM

  • wowwww this blog is so cool

    by QueenArwen, Oct 4, 2024, 8:25 AM

  • it scares me how many views this blog has

    by prettyflower, Sep 29, 2024, 9:38 AM

  • bruh
    this blog started when i was like 2 months old

    by TimmyL, Sep 27, 2024, 9:18 AM

  • 1579363 visits rn, curious how many views (if any) this blog gets now

    by EpicSkills32, Sep 16, 2024, 10:47 AM

  • interesting lol

    by EpicSkills32, Jul 27, 2024, 11:27 AM

  • EpicSkills32 reaped on Jul 27, 18:44:19 and gained 10 minutes, 57 seconds

    orz orz orz

    highest raw of the game so far

    by DuoDuoling0, Jul 27, 2024, 10:47 AM

  • whoa this blog is old

    by RocketScientist, Jun 14, 2024, 3:59 PM

  • greetings

    by EpicSkills32, May 5, 2024, 11:57 AM

  • hi$         $

    by URcurious2, Apr 13, 2024, 4:10 AM

  • orzorzorz can i have contrib :)

    by dbnl, Aug 11, 2023, 10:18 PM

  • 1.5M views pro

    by Turtle09, Sep 26, 2022, 12:11 PM

  • orz how did i not know about u before

    by russellk, Jul 10, 2021, 12:04 AM

536 shouts
Tags
blog post
Epic Item
music
video
calculus
cool facts
YouTube
Best Songs Ever 2013 CD
math
electronic music
swim team
Long Post
inspiring
Orchestra
Swimming
Christmas
Epic
Math 1A
picture
thkim1011
High Sierra Scholarship Camp
One Direction
edm
Foothill
Halo
PSAT
Anthem Lights
Other Contrib Posts
SFGiantsFan
Basketball
movie
Ncaa
Predictions
Cello
college
Contributors
CSS
dubstep
evolution
Halloween
Manic Drive
Math 1C
Noisestorm
piano
Rogue
sadface
Sequences and Series
TobyMac
trailer
Varien
2048
AP Comp Sci
Audiomachine
briantix
Chemistry
code
community college
Danyka Nadeau
Epic Item Nope
Fractal
FTW
gmail
Greed Control
Hellberg
java
LaTeX
logarithms
March Madness
mashup
Mathfights
Music taste
Muzzy
NBA
other blogs
Pegboard Nerds
plug.dj
Reaper
SAT
Spanish 1
Taylor Swift
Tristam
Tut Tut Child
World Cup
1d
2Pac
ACT
Alan Walker
amazing
AMC
anaverageaopser
Andy Mineo
Angelina Jolie
Anna Yvette
Announcements
AoPS Awards
AP Calc BC
Arbiter
Au5
avatar
Avengers
Axwell
Backstreet Boys
bandwagon
Beau Brians
Big Daddy Weave
Binomial-theorem
Blog Post Calculus
Bmt
Braken
Brick Smash
Bullseye
camping
Capital Kings
Capital Lights
cars
Cassandra Kay
Change
chaotic_iak
chillstep
Chris and Conrad
Chrisson
Christianity
Chspe
Coding
college apps
commercial
CS
Dada Life
David Guetta
dinosaurs
Disciple
dog
DotEXE
drumstep
earlvin14
earth
Evanescence
Everything Dojo
F.o.o.l.
flash games
friendship
Frozen
funny
Gears of War
google
haircut
Hawk Nelson
Hearthstone
Hillsong United
Hobbit
Hot Date
Imagine Dragons
Important
inequalities
iNexus
Instrumental Core
Intermediate Algebra
Jonny Rose
Justin Beiber
Katdrop
Knife Party
Laura Brehm
Lazslo
Lemon Jelly
Life
Lord of the Rings
Love and the Outcome
mad
Mandlebrot
MARVEL
Master Chief
Matduke
Math 241
math contest
MATHCOUNTS
Mathleague
Michael Jackson
Monstercat
Morgan Freeman
N3rv
nanobii
natural log
New Year
news
Noisecontrollers
One Punch Man
other blog
other contributors
Paul Goerge
pen spinning
Petaminx
Phil Wickham
physics
Physics 2
PiesAreSquared
Pikachu
Pixl
playlist
procrastination
programming1157
Quora
Rameses B
Razihel
Red Letter Hymnal
remix
Rich Edwards
Rootkit
Rootkitt
Sandra Bullock
SAT words
science
sea slugs
Seedleaf
sh4931
Showtek
Skillet
Sonnhard
Special
sports
Stanford
Stellar Kart
Stephen Walking
story
stufftodo
Super Bowl
Survivor
tbt
Teminite
Tenth Avenue North
Thanksgiving
The Piano Guys
Thirty Seconds to Mars
Thousand Foot Krutch
Trivecta
Two Steps From
VBS songs
Veridia
About Owner
  • Posts: 3075
  • Joined: Dec 24, 2011
Blog Stats
  • Blog created: Jan 14, 2012
  • Total entries: 600
  • Total visits: 1581954
  • Total comments: 771
Search Blog
a