Unit A: Geometry

Chapter 1: Polygons

Properties of Triangles



Eiffel Tower
The Eiffel Tower, the Golden Gate Bridge, and the Louvre Pyramid have a common connection in that they incorporate triangles.

Golden Gate Bridge

In this lesson, you will review the various types of triangles and discuss their properties. As you look at each triangle's properties, think about where you have seen triangles in structures and why the engineer or architect chose that triangle for that structure.

Entrance to the Louvre Museum
By the end of this lesson, you will be able to

  • identify the three types of triangles by side length
    • equilateral
    • isosceles
    • scalene
  • identify the three types of triangles by angle
    • acute
    • obtuse
    • right
  • find the missing angles in a triangle