# Lesson 7 – Geometry: Triangles

Geometry works with the following shapes: triangle, circle, quadrilateral, trapezoid, pentagon, hexagon, heptagon, octagon, nonagon, decagon, dodecagon, and others. These multi-sided, two-dimensional, shapes are called polygons. Polygons have straight, not curved, sides, and they are always closed. The list of polygons seems unending, but the good news is that the subtest expects you to only […]