Now, more than 122 years after it was first proposed, Kamata and two other mathematicians have finally proved that a solution ...

A geometry problem over a century old has just found its definitive answer. Mathematicians have confirmed that the solution ...

The interior angles in a triangle always add up to 180º. An equilateral triangle has 3 sides of equal length. The dashes on the lines show they are equal in length. All of the angles are also equal.

Big Idea – We can describe, measure, and compare spatial relationships. to build on students' knowledge of triangle and develop students' reasoning with properties of different classes of triangles to ...