Properties of Triangles


This cheat sheet covers the high school math concept – Properties of Triangles.

Properties of Triangles

This concept is one of the important ones and interesting under trigonometry. This chapter covers various relations between the sides and the angles of a triangle.

A good knowledge of the trigonometric ratios and basic identities is a must to understand and solve problems related to properties of triangles. A cheat sheet on Trigonometry is also available on this website.

Also, you should be comfortable with various trigonometric identites related to the triangle, also sometimes referred to as conditional trigonometric identities. A cheat sheet on Conditional Trigonometric Identities is also available on this website.

Finally, it’ll greatly help to understand various derivations in this chapter if you’re aware of all geometry theorems covered generally in middle school.

This one page PDF covers summarised theory and the most important formulas related to the concept. Keep it handy while you’re revising the concept, especially before an exam.

The topics included in this cheat sheet are:

  • Sine Rule
  • Cosine Rule
  • Tangent Rule
  • Projection Formula
  • Area of a Triangle
  • Half Angle Formulas
  • In Radius
  • Ex Radius
  • Distance between Circumcenter and Incentre
  • Distance between Circumcenter and Excentres
  • Distance between Circumcenter and Orthocenter
  • Distance between Orthocenter and Incenter
  • Distance between Incenter and Exccenters
  • Distance between Excenters

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