Rotation Made Simple

Rotation is one of the exciting parts of geometry. It means turning shapes around a point, which we call the "centre of rotation." Understanding this is important for Year 10 students as they learn about transformations.

What is Rotation?

When we rotate a shape, it changes where it is based on two things:

• Clockwise vs. Anticlockwise: We can turn shapes in either direction. For example, if we rotate a triangle 90 degrees anticlockwise, it will end up in a different spot compared to where it started.

• Angle of Rotation: The angle tells us how much to turn the shape. If we rotate it 180 degrees, it flips to the opposite side. A 90-degree rotation moves it to a side next to where it began.

Example of Rotation

Let’s think about a triangle with corners at these points: A(2, 3), B(4, 5), and C(3, 1). If we turn this triangle 90 degrees clockwise around the centre point (0, 0), we can find the new points with these rules:

• Point ( A(2, 3) ) becomes ( A' (3, -2) )
• Point ( B(4, 5) ) becomes ( B' (5, -4) )
• Point ( C(3, 1) ) becomes ( C' (1, -3) )

Drawing it Out

It can be really helpful to draw this out. Make a sketch of both the original triangle and the rotated one. This way, you can see how the rotation changes where the shape is without changing its appearance.

Important Things to Remember

• Fixed Point: The centre of rotation stays the same.
• Shape Properties: The size and shape of the figure don't change; only where it is located does.

By practicing these ideas, students will learn how rotations can change shapes on a flat surface!