A shape is drawn on a centimetre grid. Write down the order of rotational symmetry of the shape.

Answer

The shape provided is an isosceles triangle. Rotational symmetry refers to the number of times a shape can be rotated around its center point and still look the same within 360 degrees. For a non-degenerate isosceles triangle that is not equilateral, the only angle at which it looks the same is after a full 360-degree rotation. At 0 degrees (its original position) and 360 degrees (a full rotation back to its original position), the figure aligns with itself. However, when determining the 'order' of rotational symmetry, we count how many times it maps onto itself as it is rotated through 360 degrees. When considering the transformations that leave the figure unchanged, the identity transformation (0-degree rotation) is always included. For an isosceles triangle (not equilateral), the only rotation that maps the triangle onto itself is a 360-degree rotation. Since this is effectively the same as the starting position, it has an order of 1. Therefore, the order of rotational symmetry for this isosceles triangle is 1.