4 2 REFLECTIONS EX 1 HORIZONTAL AND VERTICAL

4. 2 REFLECTIONS

EX. 1 HORIZONTAL AND VERTICAL REFLECTIONS Graph triangle ABC with vertices A(1, 3); B(5, 2); C(2, 1). Tell and graph image with reflection over x = 3. Draw in line and just count how far away from line of reflection and go opposite direction the same amount A’(5, 3) left two, so go right 2 from line of reflection B’(1, 2) left one, so go right one from line of reflection C’(4, 1) right two, so go left two from line of reflection

EX. 2 REFLECTING WHEN Y = X When y = x then (a, b) → (b, a) What are coordinates for image of FG with endpoints F(-1, 2) and G(1, 2) when reflected over y=x F’(2, -1) G’(2, 1)

EX. 3 REFLECTING OVER Y = -X (a, b) → (-b, -a) Graph Quad with vertices A(-3, 2); B(1, -1); -2, -2); D(-4, -1) and image reflected over y = -x A’(-2, 3); B’(1, -1); C’(2, 2); D’(1, 4) C(

EX. 4 GLIDE REFLECTIONS Image of a translation (glide) followed by a reflection (reflection) Graph ABC with vertices A(3, 2); B(6, 3); C(7, 1) and image after a glide reflection of: Translation (x – 8, y) and reflected over x – axis Translation: A’(-5, 2); B’(-2, 3); C(-1, 1) Reflection: A’’(-5, -2); B’’(-2, -3); C(-1, -1)

YOUR PRACTICE Graph RST with vertices R(4, 1); S(7, 3); T(6, 4) with translation of (x, y – 1) and reflected over y =x Give final coordinates of glide reflection and graph image Translation: R’(4, 0); S’(7, 2); T’(6, 3) Reflection: R’’(0, 4); S’’(2, 7); T’’(3, 6)

EX. 5 SYMMETRY Flipping an image onto itself Line that does this is called the line of symmetry How many lines of symmetry? 2 None infinite F