It's possible to demonstrate and prove mathematically that the angle sum of every triangle is 180 degrees. The techniques used are useful for solving all kinds of other geometry problems too.

Linear- In linear molecular geometry, the center atom has two molecules connected to it. Bond angle is 180 degrees. Trigonal-bipyramidal- In this type of molecular geometry, the center atom is ...

Geometry! HA! Who needs it ... while another looks at different types of angles and how they relate to shapes. One final sketch explores the properties of a rhombus. This clip is from the ...