SAS similarity
One of the main 3 main theorems for proving the similarity between 
triangles. Similarity (specifically for triangles here) means all the angles in these triangles are equal and all sides are proportional to each other. SAS similarity is a similarity theorem stating that if there are two proportional sides and an angle in between it is equal, then they are similar by SAS similarity.
Example Problem: There are two isosceles triangles, 
and 
.
= 32^\circ
\overline{AB} = 9
\overline{DE} = 3\overline{BC} = 2\overline{EF} = 6
m\angle BAC, m\angle BCA, m\angle EDF
m\angle EFD$(All of these are base angles for their respective triangles)?
Example Solution: Since sides$ (Error compiling LaTeX. Unknown error_msg)\overline{AB}\overline{DE}
3\overline{EF}\overline{BC}
3
\angle B\angle E\triangle ABC\triangle DEF
2
m\angle BAC = m\angle BCA = m\angle EDF = m\angle EFD
32^\circ
\frac{(180-32)}{2}
\frac{148}{2}
74^\circ
m\angle BAC = m\angle BCA = m\angle EDF = m\angle EFD = 74^\circ$.
