12 1 Reflections Lesson 34 Reflections Do Now
- Slides: 15
12 -1 Reflections Lesson 34: Reflections Do Now: How many lines of symmetry does each figure have? Holt Geometry
12 -1 Reflections Holt Geometry Pages 178180
12 -1 Reflections or Holt Geometry T 3, 1 or 3, 1
12 -1 Reflections Holt Geometry
12 -1 Reflections Holt Geometry
12 -1 Reflections 41. No. Since the y-values are not constant, each x value would not move by the same amount. Holt Geometry
12 -1 Reflections A “ 4 letter word” we use, describes a reflection as a _____ FLIP We can reflect points or entire figures across any line. Holt Geometry
12 -1 Reflections Postulate A Line Reflection is Rigid Motion a _____ Isometry ) ( _______ Image Preimage Holt Geometry
12 -1 Reflections On your graph board, reflect the point S(3, 4) across the x-axis. Graph the preimage and image. S(3, 4) r x-axis S’(3, -4) (x, y) (x, –y). This indicates which value remains the same Holt Geometry
12 -1 Reflections What do you think will happen to the x and y values of S(3, 4) with a reflection over the y-axis? Graph the preimage and image. r S(3, 4) y-axis S’(– 3, 4) (x, y) (–x, y). This indicates which value remains the same Holt Geometry
12 -1 Reflections Reflect the point S(3, 4) across the line y = x. Graph the line y=x, then graph the preimage and image. S(3, 4) r y=x S’(4, 3) (x, y) (y, x) This is like the Converse for reflections Holt Geometry
12 -1 Reflections What do you think will happen with a reflection of S(3, 4) over the line y=-x? Graph the preimage and image. S(3, 4) r y=-x S’(– 4, – 3) (x, y) (–y, –x) This is like the Contrapositive for reflections Holt Geometry
12 -1 Reflections ACROSS THE LINE y=-x Holt Geometry (x, y) (-y, -x)
12 -1 Reflections Tonight’s HW #34 BIG IDEAS Page 186 #’s 2 -16 Holt Geometry
12 -1 Reflections EXIT SLIP Using the rules of reflections, find the new vertices of the figure reflected across the given line. 1. A(2, 3), B(– 1, 5), C(4, – 1); y = x A’(3, 2), B’(5, – 1), C’(– 1, 4) 2. U(– 8, 2), V(– 3, – 1), W(3, 3); y-axis U’(8, 2), V’(3, – 1), W’(– 3, 3) 3. E(– 3, – 2), F(6, – 4), G(– 2, 1); x-axis E’(– 3, 2), F’(6, 4), G’(– 2, – 1) Holt Geometry