230 likes | 400 Views
MA 08 Geometry. 6.9 Rotations. Goals. Identify rotations in the plane. Apply rotation formulas to figures on the coordinate plane. Rotation. A transformation in which a figure is turned about a fixed point, called the center of rotation. Center of Rotation. Rotation.
E N D
MA 08 Geometry 6.9 Rotations
Goals • Identify rotations in the plane. • Apply rotation formulas to figures on the coordinate plane. 6.9 Rotations
Rotation • A transformation in which a figure is turned about a fixed point, called the center of rotation. Center of Rotation 6.9 Rotations
Rotation • Rays drawn from the center of rotation to a point and its image form an angle called the angle of rotation. G 90 Center of Rotation G’ 6.9 Rotations
Rotations on the Coordinate Plane • Know the translation formulas for: • 90 rotations • 180 rotations • clockwise & counter-clockwise Unless told otherwise, the center of rotation is the origin (0, 0). 6.9 Rotations
90 clockwise rotation Formula (x, y) (y, x) A(-2, 4) A’(4, 2) 6.9 Rotations
Rotate (-3, -2) 90 clockwise Formula (x, y) (y, x) A’(-2, 3) (-3, -2) 6.9 Rotations
90 counter-clockwise rotation Formula (x, y) (y, x) A’(2, 4) A(4, -2) 6.9 Rotations
Rotate (-5, 3) 90 counter-clockwise Formula (x, y) (y, x) (-5, 3) (-3, -5) 6.9 Rotations
180 rotation Formula (x, y) (x, y) A’(4, 2) A(-4, -2) 6.9 Rotations
Rotate (3, -4) 180 Formula (x, y) (x, y) (-3, 4) (3, -4) 6.9 Rotations
Rotation Example B(-2, 4) Draw a coordinate grid and graph: A(-3, 0) B(-2, 4) C(1, -1) Draw ABC A(-3, 0) C(1, -1) 6.9 Rotations
Rotation Example B(-2, 4) Rotate RST 90 clockwise. Formula (x, y) (y, x) A(-3, 0) C(1, -1) 6.9 Rotations
Rotate ABC 90 clockwise. B(-2, 4) (x, y) (y, x) A(-3, 0) A’(0, 3) B(-2, 4) B’(4, 2) C(1, -1) C’(-1, -1) A’ B’ A(-3, 0) C’ C(1, -1) 6.9 Rotations
Rotate ABC 90 clockwise. B(-2, 4) Check by rotating ABC 90. A’ B’ A(-3, 0) C’ C(1, -1) 6.9 Rotations
C B D A E H F G Rotating segments O 6.9 Rotations
CE C B D A E H F G Rotating AC 90 CW about the origin maps it to _______. O 6.9 Rotations
FE C B D A E H F G Rotating HG 90 CCW about the origin maps it to _______. O 6.9 Rotations
ED C B D A E H F G Rotating AH 180 about the origin maps it to _______. O 6.9 Rotations
GH C B D A E H F G Rotating GF 90 CCW about point G maps it to _______. O 6.9 Rotations
C C B D A E A E H F G G Rotating ACEG 180 about the origin maps it to _______. EGAC O 6.9 Rotations
C B D A E H F G Rotating FED 270 CCW about point D maps it to _______. BOD O 6.9 Rotations
Practice Practice Practice 6.9 Rotations