Sankaku puzzles are a geometric based logic puzzle that focuses on finding the area of a triangle. The goal of each puzzle is to connect three dots to form a triangle with the specified area.

Sankaku puzzles are the creation of Naoki Inaba, a prolific Japanese puzzle creator. I first discovered these puzzles several years ago on Inaba’s website (which is written entirely in Japanese), and I featured them in a round-up on my blog of Japanese Logic Puzzles for the Secondary Math Classroom.

I recently ran across them again, and I decided that they deserved their own entire blog post to hopefully help them get the attention they deserve. These puzzles should be of special interest to geometry teachers or anyone who includes teaching about finding the area of triangles in their curriculum.

Inaba includes 42 of these triangle-finding puzzles on his website. They are spread over eight pages which I find really hard to print and use in my math classroom as-is.

I decided to compile the puzzles into a Word document so that they only take four pages instead of the original eight. I also added my English translation of the original Japanese instructions.

I printed these four pages in booklet mode to make a mini puzzle book of the sankaku puzzles for my students.

As you can see inside the booklet, the puzzles start out on 3 x 3 grids, but they quickly increase in difficulty to 4 x 4 grids.

I hope you and your students enjoy hunting for triangles as you solve these sankaku puzzles!

If you like these puzzles, I highly suggest you check out Naoki Inaba’s other math-based logic puzzles. His Zukei Puzzles are another great puzzle for geometry teachers!

## Free Download of Sankaku Puzzles

Full Disclosure: These puzzles are the original creation of Naoki Inaba and were originally published on Inaba’s website in Japanese.

Sankaku Puzzles – Full Size (PDF) (3181 downloads)

## Puzzle Solutions

I intentionally do not make answers to the printable math puzzles I share on my blog available online because I strive to provide learning experiences for my students that are non-google-able. I would like other teachers to be able to use these puzzles in their classrooms as well without the solutions being easily found on the Internet.

However, I do recognize that us teachers are busy people and sometimes need to quickly reference an answer key to see if a student has solved a puzzle correctly or to see if they have interpreted the instructions properly.

If you are a teacher who is using these puzzles in your classroom, please send me an email at sarah@mathequalslove.net with information about what you teach and where you teach. I will be happy to forward an answer key to you.

## More Printable Paper and Pencil Logic Puzzles

- 3-1-4 Pi Day Number Challenge
- Sankaku Puzzles
- Strimko Puzzles in the Classroom
- Square Sudokus
- Make It Pythagorean Puzzles
- Number Ball Puzzles by Naoki Inaba
- Hidato Puzzles
- Step Puzzles by Naoki Inaba – A Logic Puzzle for Introducing Arithmetic Sequences
- Kazu Sagashi Puzzles from Naoki Inaba
- Factor Tree Puzzles Inspired by Dr. Harold Reiter
- Strimko Logic Puzzles Review
- Tents and Trees Puzzles
- Slants Puzzles
- Angle Mazes by Naoki Inaba
- Zukei Puzzles
- Japanese Logic Puzzles for the Secondary Math Classroom
- Area Maze Puzzles from Naoki Inaba
- Masyu Puzzles
- KenKen In The Classroom
- Futoshiki Puzzles
- Hashi Puzzles
- Shikaku Puzzles
- Nonogram Puzzles
- Digit Cells Puzzle