Welcome to The Riddler. Every week, I offer up problems related to the things we hold dear around here: math, logic and probability. Two puzzles are presented each week: the Riddler Express for those ...

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. What is a triangle? We all know that a triangle is a three-sided shape — 1, 2, 3 sides. A triangle also ...

A triangle is a polygon. It is a closed 3-sided shape made up of straight lines. The ‘tri-’ part of the word triangle means three. A triangle has 3 sides and 3 angles. Interior angles are the angles ...