### Pythagorean theorem. We write with chalk on a board. #pythagorean #theorem #math #triangle #right #formula #algebra #angle #hypotenuse #background #class #classroom #colored #drawing #education #equal #equation #geometric #geometry #intelligence #law #learn #lecture #lesson #mathematical #mathematician #mathematics #pattern #perimeter #pythagora #right-angled #school #serious #shape #sign #square #study #studying #symbol #teach #technical #board #sine #cosine #tangent #cotangent #chalk