Other Scale Factors
In this section we shall see what happens when the scale factors become either fractions or whole numbers.
Use the slider to change the scale factor. What will happen if you change it to 0.5? Try it and see if you are correct.
What happens if the scale factor is made negative? What will happen if you change it to -2? Try this and see if you are correct.
By pressing the play button in the bottom left of the activity watch the animation for scale factors between -3 and 3.
Use the pen tool to draw the following functions of the purple shape:
Now move the blue shape over the purple shape and the green point over each centre, and change the scale factors to check your answers.
The blue shape has been enlarged about the red point to create the green shape.
Can you work out where the centre of enlargement needs to be to create each purple shape from the blue shape? What about what the scale factor is? Use the pen tool to draw the points and write down the scale factor.
Grab the red point, and move it to place the green shape over each of the purple shapes.
To change the scale factor of the enlargement use the slider.
In each case does the red point go over the point you drew?
Describe fully each enlargement.
Now draw a new point on the graph. Move one of the purple shapes to where the blue shape will end up when enlarged about this point. Move the red point to check if you are correct.
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