NZ Level 3

Rotations

Lesson

A rotation is what occurs when we turn an object or shape around a central point. The object is exactly the same shape and size, just spun around (like going in a circle). Every point on the original shape has a matching point on the new shape.

Commonly we describe rotations using a degree measure (like an angle), and as being either clockwise or anticlockwise.

Particularly at the moment you need to be able to identify rotations of:

$90^\circ$90° (a quarter turn), $180^\circ$180° (a half turn), $270^\circ$270° (a three-quarter turn) and $360^\circ$360° (a full turn) in both clockwise and anticlockwise directions.

Have a play with this interactive. Here you can change the shape that of the object and the position of the central rotation point. Notice how a rotation of $360^\circ$360° takes you right back to where you started.

Which picture shows a rotation?

Think: Which one looks like it has been spun around?

Do:

C has been translated (slid) into a different position.

B looks like a mirror image of the original. So this is a reflection (flip).

A has been spun around $180^\circ$180°. This is the rotation!

Select all the rotations.

- ABCDABCD

Which of the following figures represents the given flag after rotating it anticlockwise around the red point by 90° ?

- ABCDABCD

Which is the correct image after the original is rotated by $45^\circ$45° clockwise?

$B$

`B`A$M$

`M`B$H$

`H`C$A$

`A`D$B$

`B`A$M$

`M`B$H$

`H`C$A$

`A`D

Describe the transformations (refl ection, rotation, translation, or enlargement) that have mapped one object onto another