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

Answer

The shape shown on the grid is an isosceles triangle. An isosceles triangle is a triangle that has two sides of equal length. Consequently, the two angles opposite these sides are also equal. Rotational symmetry refers to the number of times a shape can be rotated about its center point and still look the same, before completing a full 360-degree turn. The 'order' of rotational symmetry is this number. Let's analyze the given isosceles triangle: 1. If we rotate the triangle by any angle less than 360 degrees around its center, it will not look the same as its original orientation. 2. The only way it will look the same is if it is rotated by a full 360 degrees. Therefore, an isosceles triangle only maps onto itself once in a full 360-degree rotation. This means it has a rotational symmetry of order 1. In general, all shapes have at least an order of 1 rotational symmetry, as they always look the same after a 360-degree rotation. Shapes with higher orders of rotational symmetry (e.g., a square has order 4, an equilateral triangle has order 3) map onto themselves at multiple points within a 360-degree rotation. So, the order of rotational symmetry for the given isosceles triangle is 1.