Side Angle Side (SAS) Theorem of Triangle Congruence

http://en.wikipedia.org/wiki/Congruence_%28geometry%29

30-60-90 triangles

http://www.regentsprep.org/regents/math/algtrig/att2/ltri30.htm

scalene (triangles)

adjective. Geometry.

1. (of a cone or the like) having the axis inclined to the base.
2. (of a triangle) having three unequal sides.

Origin Late Latin scalēnus < Greek skalēnós unequal

45-45-90 right triangles isoceles

https://www.khanacademy.org/math/geometry/right_triangles_topic/special_right_triangles/v/45-45-90-triangles

Using TI-30x calculator to find square root

https://www.youtube.com/watch?v=yeFxCoVimlU
Button pushes: 2nd, x2, 2, 5, = And you should get 5. The square root of 25 is 5.
Button pushes: 2nd, x2, 1, 0, = And you should get 3.16227766017

The square root of 10 is 3.16227766017

Corresponding Angles measures are equal when lines are parallel

See angles 1 and 2
know alternate interior ( 2 and 3 )
          alternate exterior ( 1 and 4)
          vertical angles ( 1 and 3) 
http://www.regentsprep.org/regents/math/geometry/gp8/lparallel.htm