University:
High School
Course:
High School Algebra
Academic year:

2021
Views:

194

Pages:

3
Author:

Primolanba

Reflections In your own words, write the meaning of each vocabulary term. reflection "mirror" or "flipped" image line of reflection line you reflect over glide reflection translation followed by a reflection reflection symmetry drawing the same on the other side line of symmetry a line drawn to split an object into two equal parts Core Concepts A reflection is a transformation that uses a line like a mirror to reflect a figure. The mirror line is called the line of reflection. A reflection in a line m maps every point P in the plane to a point P', so that for each point on of the following properties is true. If P is not on m, then m is the perpendicular bisector of PP'. If P is on m, then P = P'. Coordinate Rules for Reflections If (a, b) is reflected in the x-axis, then its image is the point (a, -b). If (a, b) is reflected in the y-axis, then its image is the point (-a, b). If (a, b) is reflected in the line y = x, then its image is the point (b, a). If (a, b) is reflected in the line y = -x, then its image is the point (-b, -a). Postulate 4.2 Reflection Postulate A reflection is a rigid motion. Everything has to be the same - shape - angles - size Extra Practice In Exercises 1-4, graph ∆ABC and its image after a reflection in the given line. A(-1, 5), B(-4, 4), C(-4, 1) x-axis A(0, 2), B(4, 5), C(5, 2) x-axis A(-2, -1), B(-4, -2), C(-1, -3) y = 1 A(-2, 3), B(-2, -2), C(0, -2) x = -3 In Exercises 5 and 6, graph the polygon's image after a reflection in the given line. y = x A(-3, 2), A'(2, -3) B(-1, 2), B'(2, -1) C(-1, 4), C'(4, -1) D(-3, 4), D'(4, -3) *rule was to flip all the #'s y = -x A(2, 2), A'(-2, -2) B(5, 3), B'(-3, -5) C(5, 1), C'(-1, -5) D(2, 1), D'(-1, -2) *rule was to flip and (-) #'s