The techniques used are useful for solving all kinds of other geometry ... 225 + 135 = 360 The sum of interior angles in a triangle is 180˚. In an equilateral triangle, all three angles are ...

You may hear students say words like ‘paralyzed’ triangle for isosceles and equilateral triangles after noticing the restrictive movements of these triangles upon dragging. Properties of symmetry: - ...

In 1907, the English author and mathematician Henry Ernest Dudeney posed a puzzle: Can any equilateral triangle be cut into ... horizons for understanding and solving dissection problems." ...

TOKYO -- A Japan-U.S. research team on March 10 offered a mathematical proof that "Dudeney's dissection," a challenge to cut an equilateral triangle and use the parts to create a square with the ...