standard_description: Use special triangles to determine geometrically the values of sine, cosine, tangent for π/3, π/4 and π/6, and use the unit circle to express the values of sine, cosines, and tangent for π–x, π+x, and 2π–x in terms of their values for x, where x is any real number.
problem_activity: List one attribute that each of the following pairs of shapes have in common. There may be more than one correct answer.
a.   Square and rhombus
b.   Square and rectangle
c.   Square and parallelogram
d.   Square and trapezoid
e.   Square and quadrilateral


aligns: no