Return to Geometry
Unit 1.2
POLYGONS
& CIRCLES
From the stability of the Triangle to the perfection of the Circle. Understanding the properties of closed shapes is the key to measuring the world.
NATURE'S GEOMETRY
The Hexagon is the most
efficient shape in nature.
efficient shape in nature.
The Infinite Limit
What happens when you add more sides to a polygon? The edges smooth out. The vertices blend together. Eventually, a Polygon becomes a Circle.
Shape Shifter
Triangle
3 (Triangle)∞ (Circle)
Sum of Angles180°
One Angle60.0°
r = 120 units
Shape Classification
Polygon
General
A closed plane figure made up of three or more line segments.
Regular Polygon
Classification
A polygon that is both equilateral (equal sides) and equiangular (equal angles).
Vertex
Anatomy
The point where two sides of a polygon meet.
Convex vs Concave
Classification
Convex: All vertices point outwards. Concave: At least one vertex points inwards ("caves in").
Chord
Circle
A segment whose endpoints lie on a circle. The diameter is the longest chord.
Tangent
Circle
A line that touches a circle at exactly one point. It is perpendicular to the radius at that point.