MEASURE
LO:TRANSFORMATIONS
- - TRANSFORM A 2D SHAPE BY ROTATING AND
DESCRIBE A ROTATION CORRECTLY (INCLUDING TURN,
DIRECTION, CENTRE OF ROTATION)
DO NOW: FIND THE INVERSE TRANSLATE
TRANSFORMATION:
Reflection
Rotation
Translation
Enlargement
Rotation
Rotation is a type of
transformation.
A rotation turns an object. The
size and shape stay exactly the
same but the orientation
changes.
We describe rotations with an
angle, a direction and a centre.
Rotation - Standard
Rotating shapes:
To rotate a shape you need to know 3 things:
1. Degrees to rotate
2. Direction
3. Centre of rotation
0/360
Clockwise
90
270
Anti Clockwise
180
Rotation
Transformation
Describing Rotations
To describe a rotation we need to know three things:
The angle of the rotation.
For example,
½ turn = 180°
¼ turn = 90°
¾ turn = 270°
The direction of the rotation.
For example, clockwise or anticlockwise.
The centre of rotation.
This is the fixed point about which an object moves.
10
Transform this
triangle by the
rotation:
90° clockwise
around (4, 5)
9
8
Identify the
centre of
rotation.
7
6
5
4
3
2
1
0
0
1
2
3
4
5
6
7
8
9
10
Rotation - Standard
Rotate the shape 90o clockwise about the point
Rotation
Transformation
Rotation - Standard
Rotate the shape 180 about the point
Rotation
Transformation
DO THE
WORKSHEET
Enlargement
Scale Factor
Negative
Standard
Enlargement
Transformation
Enlargement – Scale Factor
Enlarging a shape means changing its size whilst keeping it's mathematical
proportion.
The shape can get bigger:
And the shape can get smaller:
(We still call this enlargement …. You will see later.
Enlargement
Transformation
Enlargement – Scale Factor
We use a SCALE FACTOR tell us how big (or small) to make the new shape.
To use a scale factor you multiply each length by the given value
Enlarge by a scale
factor of 2
Enlargement
Transformation
Enlargement - Standard
The other piece of information given to us when enlarging a shape is the
centre of enlargement.
With a centre of enlargement you must also enlarge the distance between
the shape and the given point as well as the shape.
Enlargement
Transformation
Enlargement - Negative
A negative scale factor affects the direction in which we enlarge.
For example: If I Enlarge the shape by a scale factor of -1 about the point.
Enlargement
Transformation
Enlargement - Negative
Enlarge the shape by a scale factor of -2 about the point.
Enlargement
Transformation
DO THE WORKSHEET