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

Answer

The shape shown is an isosceles triangle. An isosceles triangle is a triangle that has two sides of equal length. In the given grid, the base of the triangle spans 6 units, and the apex of the triangle is directly above the midpoint of the base, 3 units high. This confirms it is an isosceles triangle (not an equilateral or scalene triangle). Rotational symmetry is the number of times a figure can be rotated about its center point and still look the same. The 'order' of rotational symmetry is the number of distinct orientations in which the shape looks identical as it is rotated through 360 degrees. For an isosceles triangle that is not equilateral, the only rotation that will make the shape look identical to its original position is a full rotation of 360 degrees. Therefore, it only maps onto itself once in a full turn. Hence, the order of rotational symmetry for this isosceles triangle is 1.