Which figure has an order of rotational symmetry equal to 3 ? Isosceles triangle Equilateral triangle Rectangle Square

Step 1 ：The order of rotational symmetry of a figure is the number of times you can rotate it to 360 degrees and it still looks the same.

Step 2 ：An isosceles triangle has an order of rotational symmetry of 1 because it only looks the same once in a 360 degree rotation (when it is back to its original position).

Step 3 ：A rectangle also has an order of rotational symmetry of 2 because it looks the same twice in a 360 degree rotation (once when it is back to its original position and once when it is upside down).

Step 4 ：A square has an order of rotational symmetry of 4 because it looks the same four times in a 360 degree rotation.

Step 5 ：An equilateral triangle, however, has an order of rotational symmetry of 3 because it looks the same three times in a 360 degree rotation.

Step 6 ：Therefore, the figure with an order of rotational symmetry equal to 3 is the equilateral triangle.

Step 7 ：Final Answer: \(\boxed{\text{Equilateral triangle}}\)