Geometry is a concept even I found difficult, but when I look at a shape algebraically and 'balance' all 3, 4, 5, 6 angles of any shape then the answer is simple.  I will start anyone off with simple algebra, once confident, a bit harder algebraic concepts.

Proud when one student could not catch on to how to determine if a shape was equal to 180, 360, and so on.  After almost 4 sessions he began to understand, we continued his learning during his spring break and then he returned to school where he taught the class and the teacher how to calculate any shape!

Present a question; I will break it down for even you to understand!