[zero afterstartingat(1,0).Twoanglesofthissizeaddtogethertobea(*)straight angle, and any two angles that sum to this size are called complementary.
A reference angle of this size in standard position on the unit circle terminates at the point (0,1) [zero afterstartingat(1,0).Twoanglesofthissizeaddtogethertobea(*)straight angle, and any two angles that sum to this size are called complementary. For ten points, name this value thatdescribes one-fourth of a circular rotation or the size of a right angle.
A reference angle of this size in standard position on the unit circle terminates at the point (0,1)
90 degrees (accept pi over 2 radians or 100 gradians; prompt on "90" or "pi over 2" by asking "in what unit?")