#67 Finding the angle in an Isosceles triangle
#94 Interior angles of a triangle
#96 Determining why triangles are congruent
#97 Determining why triangles are similar
#98 Types of triangles
#99 Exterior angle of a triangle
#100 The four conditions of congruency
#101 Determining the length of a side in similar triangles
#124 Isosceles triangles and parallel lines
#125 Congruency of right angle triangles
#126 Similarity of two triangles with equal angles
#209 Congruency vs similarity
#210 Basic triangle and straight line theorems
#232 Congruency and triangles
#233 Basic triangle theorems
#235 Congruency and triangles
#236 Similarity of two triangles
#249 Some geometry basics
#251 Solving as a function of x in an isosceles triangle
#252 Choosing the congruent triangle using SAS
#253 Using circle geometry to prove congruency
#254 Congruency of triangles with follow up questions
#260 Similarity of triangles and calculating the length of a side