Skill: Recognize half turns

A half turn means turning a shape halfway around: two right angles, or $(180^\circ)$.

When a shape makes a half turn:

• it keeps the same size and shape;
• it ends up facing the opposite direction;
• each part moves to the opposite side of the turning point.

A half turn is a turn, not a flip or reflection.

Example

Is Shape B a half-turn of Shape A?

Shape A

    ▲
●   ■

Shape B

■   ●
    ▼

Work it out step by step:

1. Use the square $■$ as the middle of the turn.
2. The triangle is above the square in Shape A. After a half turn, it should be below the square. Shape B has $▼$ below it.
3. The circle is left of the square in Shape A. After a half turn, it should be right of the square. Shape B has the circle on the right.
4. The shape has not been stretched or changed. It has simply turned halfway around.

So, yes, Shape B is a half-turn of Shape A.