Geometry

Lines, Rays, Segments

Line · Ray · Segment.

Types of Angles

Acute · Right · Obtuse · Reflex.

Triangles by Sides

3 equal · 2 equal · 0 equal.

Triangles by Angles

Acute · Right · Obtuse.

Quadrilaterals

Six shapes, angles sum to 360°.

3D Solids

Euler: F + V − E = 2.

Parts of a Circle

Diameter = 2 × radius. Longest chord = diameter.

Line Symmetry

Square: 4 · Rectangle: 2 · Circle: ∞ · Scalene Δ: 0.

Rotational Symmetry

Square: 4 · Equilateral Δ: 3 · Circle: ∞.