Each angle is the same size. Each angle is 60°. Image caption, An equilateral triangle has three lines of symmetry. There are three ways the triangle can be cut into a pair of mirrored halves.

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 ...

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 ...

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