👉 Learn how to prove that two triangles are congruent. Two or more triangles are said to be congruent if they have the same shape and size. There are many postulates and theorems to determine whether ...

Michael Freedman’s momentous 1981 proof of the four-dimensional Poincaré conjecture was on the verge of being lost. The editors of a new book are trying to save it. One of the most important pieces of ...

CHAMPAIGN, Ill. – A new study co-written by a University of Illinois expert in math education suggests that incorporating technology in high school-level geometry classes not only makes the teaching ...