Lesson 3: Rotating Lesson 3: Rotating ShapesShapes

Some Things to Some Things to Remember…Remember…

Visualize Visualize how the shape is rotatinghow the shape is rotating What is a 90° turn?What is a 90° turn? What is a 180° turn?What is a 180° turn? What is a 270° turn?What is a 270° turn? What is a 360° turn?What is a 360° turn? - How would you explain these turns as - How would you explain these turns as

fractions?fractions? Clockwise TurnClockwise Turn - Turning - Turning rightright Counter Clockwise TurnCounter Clockwise Turn - Turning - Turning leftleft

Do You See This Image???Do You See This Image???

Look At It Now…Look At It Now…

How was this shape rotated???

Now Look…Now Look…

How much has the shape been rotated?

Look ONE MORE TIME!!!Look ONE MORE TIME!!!How much has it been rotated???

Other Things to Other Things to Remember…Remember…

If an object is moved a certain amount, the If an object is moved a certain amount, the vertexvertex on that object moves that amount also on that object moves that amount also

- Ex: Object moves 90°, vertex moves 90° - Ex: Object moves 90°, vertex moves 90° alsoalso

The size and shape of the resulting image are The size and shape of the resulting image are congruentcongruent

The orientation is The orientation is differentdifferent Note: Note: Objects rotate from a Objects rotate from a CENTRE OF CENTRE OF

ROTATIONROTATION

- May be - May be inside inside or or outsideoutside of the object of the object

ExampleExample

How to RotateHow to Rotate Find your Centre of RotationFind your Centre of Rotation Place the Place the top of your penciltop of your pencil on the centre of on the centre of

rotationrotation Turn your pageTurn your page the amount it asks (ex: 90 the amount it asks (ex: 90° °

clockwise)clockwise) - Now your object - Now your object looks differentlooks different (turned on (turned on

the side, or up or down)the side, or up or down) - You draw your new object - You draw your new object exactly the way exactly the way

it looks rotated!!! it looks rotated!!! (we will now come back to (we will now come back to those other triangles) those other triangles)

- Tracing out your object can help you - Tracing out your object can help you remember how it is supposeed to be rotatedremember how it is supposeed to be rotated

QuestionQuestion On grid paper draw trapezoid ABCD with vertices On grid paper draw trapezoid ABCD with vertices

A(2, 4), B(7, 4), C(7, 8) and D(4, 8). A(2, 4), B(7, 4), C(7, 8) and D(4, 8). Draw the image of the trapezoid each time and Draw the image of the trapezoid each time and

color it as indicated.color it as indicated. - Rotate trapezoid ABCD (90º) turn clockwise - Rotate trapezoid ABCD (90º) turn clockwise

about C(9, 8) and color the image blue.about C(9, 8) and color the image blue. - Rotate trapezoid ABCD (180º) turn about a - Rotate trapezoid ABCD (180º) turn about a

point at (10, 9) and color the image red.point at (10, 9) and color the image red. - Rotate trapezoid ABCD (270º) turn counter - Rotate trapezoid ABCD (270º) turn counter

clockwise about a point at (9, 4) and color the clockwise about a point at (9, 4) and color the image yellow.image yellow.

Write the coordinates of the vertices of each Write the coordinates of the vertices of each rotated image. Describe if the centre of rotation rotated image. Describe if the centre of rotation has an effect on the location of the image.has an effect on the location of the image.

QuestionsQuestions

Read about Rotating shapes pages Read about Rotating shapes pages 152-153152-153

2-7 on pages 154-1552-7 on pages 154-155