www numeracysoftware com Rotational Symmetry M 6 G

www. numeracysoftware. com Rotational Symmetry M 6 G 1 b – Investigate rotational symmetry, including degree of rotation.

www. numeracysoftware. com Vocabulary 1) Rotate – to turn a figure around a fixed point 2) Point of rotation - the point around which a figure is rotated (a. k. a. the center of rotation) 3) Rotational Symmetry – when a figure fits exactly on top of itself after a rotation of 180° or less 4) Angle of rotation – the smallest angle a figure can be rotated to look exactly the same

www. numeracysoftware. com A square has rotational symmetry. • The smallest angle a figure can be rotated and still look the same is called the angle of rotation. • What is the angle of rotation of a square? 90°

www. numeracysoftware. com Does a rectangle have rotational symmetry? What is the degree of rotation? 180°

www. numeracysoftware. com Does each figure have rotational symmetry? 360 ÷ 4 = 90 360 ÷ 3 = 120 360 ÷ 6 = 60 To find the degree of rotation mathematically, divide ______ 360° by the number of times the repeats. pattern _____

www. numeracysoftware. com Do these figures have rotational symmetry? Yes - 90° Yes - 180° NO Yes - 72° Yes - 45° NO

www. numeracysoftware. com Rotational Symmetry in the Alphabet Which letters have rotational symmetry? For those with rotational symmetry, what is the degree of rotation? A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 180° 180°

www. numeracysoftware. com Rotational Symmetry all around us Which road signs have rotational symmetry?

www. numeracysoftware. com Rotational Symmetry all around us 120° 180°

www. numeracysoftware. com Rotational Symmetry all around us 90° 120° 180°

www. numeracysoftware. com Rotational Symmetry all around us 120° 180°