Two-dimensional (2D) shapes
Space
Definition
Two-dimensional (2D) shapes are those that lie on a plane. The two-dimensions are length and width. 2D shapes with straight sides are known as polygons. (Siemon, et al., 2015)
The term 'polygon' is derived from the Greek words meaning 'many angles' and refers to closed shapes with three or more angles and sides. A polygon can be described as either regular or irregular.
A 'feature' of a shape or object is an observable attribute of a shape or object. A 'property' of a shape or object is an attribute that requires mathematical knowledge to be identified. (NSW Mathematics K-10 Syllabus)
Teaching and learning activities
The resources below provide targeted teaching strategies to support student improvement in this skill.
Each downloadable lesson activity includes:
learning intentions
a list of required resources
a step-by-step lesson sequence
printable classroom materials
Select the download all icon to download all available activities or select each activity separately.
PLAN2 Areas of focus
An Areas of focus template has been created in PLAN2 to support targeted teaching of Text structure in your learning area.
Search for the DoE template titled ‘DoE HSCMinStd Writing: Text structure’ in the Areas of focus template library tab within the Plan menu, and customise it for your students’ needs.
For more information about using PLAN2 Areas of focus templates with this resource, visit the Using this resource with PLAN2 page.
Relevance to the numeracy test marking
The feedback for a Level 3 performance in the HSC minimum standard online numeracy test states:
Individuals performing at this level typically “select appropriate strategies from a variety of everyday mathematical processes in familiar and some less familiar contexts”.
Students are able to use, visualise, identify, describe and apply their understanding of key features and properties of common 2D shapes in the environment.
Connections with ACSF Level 3 descriptors
The relevant Level 3 ACSF descriptors for numeracy are shown here to demonstrate how identifying and describing properties of 2D shapes are assessed in the HSC minimum standard online test. The performance features identified show what a student is able to do in order to achieve at this level and are provided to support teachers to understand what is required to achieve a Level 3 in this skill.
Numeracy Indicator 3.09: Selects and interprets mathematical information that may be partly embedded in a range of familiar, and some less familiar, tasks and texts
Focus area: Complexity of mathematical information
Level 3 performance features:
interprets and comprehends familiar and routine 2D shapes
Numeracy Indicator 3.10: Selects from and uses a variety of developing mathematical and problem solving strategies in a range of familiar and some less familiar contexts
Focus area: Mathematical knowledge and skills: measurement and geometry
Level 3 performance features:
applies knowledge of properties of 2D shapes to describe and draw everyday objects
Connections with Numeracy Learning Progression:
The progressions describe a typical developmental sequence of literacy and numeracy learning. The numeracy progression sub-elements, levels and indicators relevant to 2D shapes are provided here to assist teachers to identify students’ capabilities and needs to support targeted teaching.
Element: Measurement and Geometry
Sub-element: Understanding geometric properties (UGP)
UGP2 — Features of shapes and objects
identifies and describes features of shapes and objects (e.g. sides, corners, faces, edges and vertices)
sorts and classifies familiar shapes and objects based on obvious features (e.g. triangles have three sides; a sphere is round like a ball)
UGP2 — Transformations
identifies features of shapes of different sizes and in different orientations in the environment following basic one-step translations, reflections or rotations (e.g. using a half turn, flipping the shape over)
UGP3 — Properties of shapes and objects
describes and identifies the two-dimensional shapes represented by the faces of three-dimensional objects (e.g. recognises the faces of a triangular prism as triangles and rectangles)
UGP3 — Transformations
determines whether a shape has line symmetry (e.g. folds paper cut-outs of basic shapes to demonstrate which has line symmetry and which does not)
identifies symmetry in the environment
UGP4 — Properties of shapes and objects
classifies two-dimensional shapes according to their side and angle properties (e.g. describes a square as a regular rectangle)
identifies key features of shapes (e.g. explains that quadrilaterals have two diagonals however they are not always equal in length)
UGP4 — Transformations
identifies that shapes can have rotational symmetry (e.g. ‘this drawing of a flower is symmetrical; I can spin it around both ways and it always looks exactly the same’)
creates symmetrical designs using a range of shapes and identifies the type of symmetry as appropriate
UGP5 — Transformations
uses combinations of reflecting, translating and rotating shapes to describe and create patterns and solve problems