In our mind’s eye, the universe seems to go on forever. But using geometry we can explore a variety of three-dimensional shapes that offer alternatives to “ordinary” infinite space. When you gaze out ...

Interior angles in a triangle add up to 180˚. Triangles close triangleA polygon with three straight sides. have three sides, therefore they have three angles. Interior angles in a triangle sum to a ...

Before reading this guide, it may be helpful to read the guides from Module 1 on the properties of angles and the properties of 2D shapes. The sum of the angles inside any polygon can be found by ...