1. Your warm up is on the back table, on blue paper.

2. Welcome to Geometry. Please do the following warm up: ____ Rhombus ____ Cube ____ Pentagon ____ Regular pentagon ____ Hexagon ____ Regular hexagon ____ Square ____ Isosceles triangle ____ Obtuse triangle ____ Right triangle ____ Acute triangle ____ Equilateral triangle ____ Trapezoid ____ Rectangle ____ Cylinder Match the shape with it’s nameA O N M L All sides are congruent. All angle measures are equal. K J I All sides are congruent. All angle measures are equal. H G F E D C B CMKINLJFABGEDOHCMKINLJFABGEDOH

3. Rigid Transformations Transformations that do not change shape or size. Pre-image is the original shape Image is the shape that undergoes a transformation

4. NOTATION For instance a triangle would be called ABC. This is the pre-image. The image of triangle ABC is called A’B’C’ (said, “A prime, B prime, C prime”). This is so we can tell the difference between the 2 identical figures.

5. Transformations There are 3 types of rigid transformations: –Translation – shapes slide –Rotation – shapes turn –Reflection – shapes flip

6. Translation Shapes slide –Every point of a figure moves in a straight line, all points move the same distance and same direction. A A’

7. Rotation Rotations turn –Every point of a figure moves around a given point called the center of rotation. A A’ Notice the center of rotation can be inside or outside of the shape B’ B

8. Reflection Reflections flip. –In a reflection, a line plays the role of a mirror. Every point in a figure is ‘flipped’ across the line. A A’

9. Summary What is the movement of a rotation? –What does is ‘turn’ around? What is the movement of a translation? –What does it ‘slide’ on? What is the movement of a reflection? –What does it ‘flip’ over? When can the pre-image and the image be a different size? How do you notate the image and the pre- image? (use point A for example)

10. Quick review Obtuse triangle – contains one obtuse angle Acute triangle – all angles  90° Right triangle – contains one 90° angle Equilateral – all sides have the same measure Equiangular – all angles are congruent Equilateral triangle – all SIDES have the same measure AND all angles are congruent.

11. New vocabulary Midpoint – is the point in the middle of a line segment. Since it is in the middle, the sides on either side of the midpoint are congruent. Line segment midpoint

12. Rotational symmetry – a shape has rotational symmetry if you can rotate it and it ‘lands on itself’. Rotational symmetry is measured in degrees. An object does not have rotational symmetry at 0° and 360°. Think of H. Does H have rotational symmetry? (yes) At how many degrees? (180°) Think of E. Does E have rotational symmetry? (no) At how many degrees? (only at 0° and 360°, so it doesn’t count)

13. Reflectional symmetry – a shape has reflectional symmetry if it has a line of symmetry Think of H. Does H have reflectional symmetry? (yes) Where is the line of symmetry? (there are two; one vertical and one horizontal) Think of F. Does F have reflectional symmetry? (no – it does not have a line of symmetry)

14. Hop in the Way-Back Machine SLOPES OF LINES y = mx + b How can you tell if two lines are parallel? How can you tell if two lines are perpendicular? How can you tell if two lines are neither parallel or perpendicular? slopes are the same slopes are the negative reciprocal of each other The slopes have no relationship. m is the slope b is the y-intercept

15. Your assignment pg 42: 82, 83ab, 84 – 86 pg 48: 92 – 96 (not 94d)