ka April Highlights and 2025 AoPS Online Class Information
jlacosta0
Apr 2, 2025
Spring is in full swing and summer is right around the corner, what are your plans? At AoPS Online our schedule has new classes starting now through July, so be sure to keep your skills sharp and be prepared for the Fall school year! Check out the schedule of upcoming classes below.
WOOT early bird pricing is in effect, don’t miss out! If you took MathWOOT Level 2 last year, no worries, it is all new problems this year! Our Worldwide Online Olympiad Training program is for high school level competitors. AoPS designed these courses to help our top students get the deep focus they need to succeed in their specific competition goals. Check out the details at this link for all our WOOT programs in math, computer science, chemistry, and physics.
Looking for summer camps in math and language arts? Be sure to check out the video-based summer camps offered at the Virtual Campus that are 2- to 4-weeks in duration. There are middle and high school competition math camps as well as Math Beasts camps that review key topics coupled with fun explorations covering areas such as graph theory (Math Beasts Camp 6), cryptography (Math Beasts Camp 7-8), and topology (Math Beasts Camp 8-9)!
Prealgebra 1
Sunday, Apr 13 - Aug 10
Tuesday, May 13 - Aug 26
Thursday, May 29 - Sep 11
Sunday, Jun 15 - Oct 12
Monday, Jun 30 - Oct 20
Wednesday, Jul 16 - Oct 29
Introduction to Algebra A
Monday, Apr 7 - Jul 28
Sunday, May 11 - Sep 14 (1:00 - 2:30 pm ET/10:00 - 11:30 am PT)
Wednesday, May 14 - Aug 27
Friday, May 30 - Sep 26
Monday, Jun 2 - Sep 22
Sunday, Jun 15 - Oct 12
Thursday, Jun 26 - Oct 9
Tuesday, Jul 15 - Oct 28
Introduction to Counting & Probability
Wednesday, Apr 16 - Jul 2
Thursday, May 15 - Jul 31
Sunday, Jun 1 - Aug 24
Thursday, Jun 12 - Aug 28
Wednesday, Jul 9 - Sep 24
Sunday, Jul 27 - Oct 19
Introduction to Number Theory
Thursday, Apr 17 - Jul 3
Friday, May 9 - Aug 1
Wednesday, May 21 - Aug 6
Monday, Jun 9 - Aug 25
Sunday, Jun 15 - Sep 14
Tuesday, Jul 15 - Sep 30
Introduction to Algebra B
Wednesday, Apr 16 - Jul 30
Tuesday, May 6 - Aug 19
Wednesday, Jun 4 - Sep 17
Sunday, Jun 22 - Oct 19
Friday, Jul 18 - Nov 14
Introduction to Geometry
Wednesday, Apr 23 - Oct 1
Sunday, May 11 - Nov 9
Tuesday, May 20 - Oct 28
Monday, Jun 16 - Dec 8
Friday, Jun 20 - Jan 9
Sunday, Jun 29 - Jan 11
Monday, Jul 14 - Jan 19
Intermediate: Grades 8-12
Intermediate Algebra
Monday, Apr 21 - Oct 13
Sunday, Jun 1 - Nov 23
Tuesday, Jun 10 - Nov 18
Wednesday, Jun 25 - Dec 10
Sunday, Jul 13 - Jan 18
Thursday, Jul 24 - Jan 22
MATHCOUNTS/AMC 8 Basics
Wednesday, Apr 16 - Jul 2
Friday, May 23 - Aug 15
Monday, Jun 2 - Aug 18
Thursday, Jun 12 - Aug 28
Sunday, Jun 22 - Sep 21
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)
MATHCOUNTS/AMC 8 Advanced
Friday, Apr 11 - Jun 27
Sunday, May 11 - Aug 10
Tuesday, May 27 - Aug 12
Wednesday, Jun 11 - Aug 27
Sunday, Jun 22 - Sep 21
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)
AMC 10 Problem Series
Friday, May 9 - Aug 1
Sunday, Jun 1 - Aug 24
Thursday, Jun 12 - Aug 28
Tuesday, Jun 17 - Sep 2
Sunday, Jun 22 - Sep 21 (1:00 - 2:30 pm ET/10:00 - 11:30 am PT)
Monday, Jun 23 - Sep 15
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)
AMC 10 Final Fives
Sunday, May 11 - Jun 8
Tuesday, May 27 - Jun 17
Monday, Jun 30 - Jul 21
AMC 12 Problem Series
Tuesday, May 27 - Aug 12
Thursday, Jun 12 - Aug 28
Sunday, Jun 22 - Sep 21
Wednesday, Aug 6 - Oct 22
Introduction to Programming with Python
Thursday, May 22 - Aug 7
Sunday, Jun 15 - Sep 14 (1:00 - 2:30 pm ET/10:00 - 11:30 am PT)
Tuesday, Jun 17 - Sep 2
Monday, Jun 30 - Sep 22
Let be a point on the Neuberg cubic. Let the lines through respectively perpendicular to form a triangle . Show that as varies, the Nine Point Circle of goes through a fixed point.
is a triangle with . is a point on , and is the midpoint of . is an altitude. is the circumcenter of , and is the midpoint of . Show that and are similar.
is a triangle with . is a point on , and is the midpoint of . is an altitude. is the circumcenter of , and is the midpoint of . Show that and are similar.
is a triangle with . is a point on , and is the midpoint of . is an altitude. is the circumcenter of , and is the midpoint of . Show that and are similar.
maybe I should have added the figure given, I though it was an easy figure to draw someone, it may contains more than those written in the text.
parmenides51 wrote:
is a triangle with . is a point on , and is the midpoint of . is an altitude. is the circumcenter of , and is the midpoint of . Show that and are similar.
maybe I should have added the figure given, I though it was an easy figure to draw someone, it may contains more than those written in the text.
parmenides51 wrote:
is a triangle with . is a point on , and is the midpoint of . is an altitude. is the circumcenter of , and is the midpoint of . Show that and are similar.
O... is the circumcenter, not incenter... Sorry...
Let be a point such that . Join . Since is cyclic (), we know that ; and further, , since . This way, as and , then .
And it is known that , since is right.
Since , which implies that .
Since , which implies that . This way, combining both equalities, ; observe that , which means that, due to SAS Similarity, . Then, . Since , where is the intersection of and , we now know that ; that is, .
Join . Since is cyclic, the circumcenter of , which is , will also be the circumcenter of (this is true since will be the center of ). Since is right, its circumcenter will lie in the hypotenuse , and, in particular, in the midpoint of . Then, is the midpoint of .
Join . Since and , we know that ; due to Thales' Intercept Theorem, this means that . Since and , then . Joining , since , due to Thales' Intercept Theorem, . Then, as ,; that is, .
Let's join . So far, we know that . Let be the foot of the perpendicular from to . It is easily provable that (since ). Then, ; that is, . Since , and , by SAS Similarity, .
This post has been edited 2 times. Last edited by DepressedCubic, Nov 25, 2020, 12:07 AM
Construct circles with diameter and . Let be the intersection of said circles, with . By Miquel's Theorem, is cyclical.
Claim 1:.
Since are the centers of the circles and in the figure, we have that . Since and are the midpoints of and , we have , and .
Then triangles and are similar, by the AAA criterion.