Complementary angles are angles that the sum of their measures is equal to 90º.

File:Complementary angles|thumbnail|center </gallery> ]] Supplementary angles are angles that the sum of their measures is equal to 180º.

 90º              __|__               90º
_________________|__|__|____________________

Vertical Angles

In the above diagram, A and C are vertical angles, and B and D are vertical angles. Vertical angles are congruent.

Exercises

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• Geometry Main Page
• Motivation
• Introduction
• Geometry/Chapter 1 Definitions and Reasoning (Introduction)
  • Geometry/Chapter 1/Lesson 1 Introduction
  • Geometry/Chapter 1/Lesson 2 Reasoning
  • Geometry/Chapter 1/Lesson 3 Undefined Terms
  • Geometry/Chapter 1/Lesson 4 Axioms/Postulates
  • Geometry/Chapter 1/Lesson 5 Theorems
  • Geometry/Chapter 1/Vocabulary Vocabulary
• Geometry/Chapter 2 Proofs
• Geometry/Chapter 3 Logical Arguments
• Geometry/Chapter 4 Congruence and Similarity
• Geometry/Chapter 5 Triangle: Congruence and Similiarity
• Geometry/Chapter 6 Triangle: Inequality Theorem
• Geometry/Chapter 7 Parallel Lines, Quadrilaterals, and Circles
• Geometry/Chapter 8 Perimeters, Areas, Volumes
• Geometry/Chapter 9 Prisms, Pyramids, Spheres
• Geometry/Chapter 10 Polygons
• Geometry/Chapter 11 ${\displaystyle \mathbb {R} ,\mathbb {R} ^{2},\mathbb {R} ^{3}}$
• Geometry/Chapter 12 Angles: Interior and Exterior
• Geometry/Chapter 13 Angles: Complementary, Supplementary, Vertical
• Geometry/Chapter 14 Pythagorean Theorem: Proof
• Geometry/Chapter 15 Pythagorean Theorem: Distance and Triangles
• Geometry/Chapter 16 Constructions
• Geometry/Chapter 17 Coordinate Geometry
• Geometry/Chapter 18 Trigonometry
• Geometry/Chapter 19 Trigonometry: Solving Triangles
• Geometry/Chapter 20 Special Right Triangles
• Geometry/Chapter 21 Chords, Secants, Tangents, Inscribed Angles, Circumscribed Angles
• Geometry/Chapter 22 Rigid Motion
• Geometry/Appendix A Formulae
• Geometry/Appendix B Answers to problems
• Appendix C. Geometry/Postulates & Definitions
• Appendix D. Geometry/The SMSG Postulates for Euclidean Geometry