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Dec
9
Fun Holiday – Pythagorean Theorem Day

Pythagorean Theorem Day or Pythagoras Theorem Day is celebrated when the sum of the squares of the first two digits in a date equals the square of the last digit in the date.

The Pythagorean Theorem is one of the basic theorems in mathematics.

Every school child around the world learns the Pythagorean Theorem.

©bigstockphoto.com/First Bite

The holiday gets its name from Pythagoras' Theorem, which defines the relationship between the sides of a right triangle or a right-angled triangle – a triangle where one angle is at 90 degrees. According to the Theorem, in a right triangle, the square of the hypotenuse (the longest side of the triangle) is equal to the sum of the square of the other two sides. The Theorem is named after Greek mathematician and philosopher, Pythagoras, who is thought to have formulated the proof for it.

The holiday is also sometimes called Right Triangle Day or Pythagoras Day.

Upcoming Pythagorean Theorem Days

Whether you write your dates in the mm/dd/yy format or the dd/mm/yy format, here are some dates you can celebrate this unique mathematical holiday in the near future.

  • August 15, 2017 (8/15/17 or 15/8/17): 8² + 15² = 17²
  • December 16, 2020 (12/16/20 or 16/12/20): 12² + 16² = 20²
  • July 24, 2025 (7/24/25 or 24/7/25): 7² + 24² = 25²

Other Mathematical Holidays

You don't have to wait for Pythagorean Theorem Day to celebrate mathematics. There are several other mathematical holidays throughout the year that honor mathematicians and their work. Some of these include Square Root Day, e-Day, Pi Day, Tau Day, Yellow Pig Day, Pi Approximation Day, and Fibonacci Day.

How to Celebrate?

Here are some ways you can make the most of this uncommon holiday:

  • Learn more about the Pythagoras Theorem and its real life applications.
  • Celebrate the day by eating foods that are cut in right angle triangles. Make a pizza or bake a cake or cookies in the shape of a right triangle. Too much work for you? Why not make triangular Rice Krispie treats?
  • Since the holiday depends on a unique date pattern, why not spend the day learning about other special date patterns. Use our Date Pattern Calculator to find out when's the next Sequential or Palindrome Day.

Did You Know...

...that dates and numbers that fulfill the relationship defined by the Pythagorean Theorem are called Pythagorean triples?

Pythagorean Theorem Day Observances

Fun Holiday: Pythagorean Theorem Day Observances
YearWeekdayDateName
2020WedDec 16Pythagorean Theorem Day
2025ThuJul 24Pythagorean Theorem Day

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January 2015
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    123
45678910
11121314151617
18192021222324
25262728293031
February 2015
SMTWTFS
1234567
891011121314
15161718192021
22232425262728
March 2015
SMTWTFS
1234567
891011121314
15161718192021
22232425262728
293031    
April 2015
SMTWTFS
   1234
567891011
12131415161718
19202122232425
2627282930  
May 2015
SMTWTFS
     12
3456789
10111213141516
17181920212223
24252627282930
31      
June 2015
SMTWTFS
 123456
78910111213
14151617181920
21222324252627
282930    
July 2015
SMTWTFS
   1234
567891011
12131415161718
19202122232425
262728293031 
August 2015
SMTWTFS
      1
2345678
9101112131415
16171819202122
23242526272829
3031     
September 2015
SMTWTFS
  12345
6789101112
13141516171819
20212223242526
27282930   
October 2015
SMTWTFS
    123
45678910
11121314151617
18192021222324
25262728293031
November 2015
SMTWTFS
1234567
891011121314
15161718192021
22232425262728
2930     
SMTWTFS
  12345
6789101112
13141516171819
20212223242526
2728293031  

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