# Classify two-dimensional figures based on the presence or absence of parallel or perpendicular

### Cluster

Draw and identify lines and angles and classify shapes by properties of their lines and angles.

Evidence of Learning Statements

 Students with a level 1 understanding of this standard will most likely be able to: Students with a level 2 understanding of this standard will most likely be able to: Students with a level 3 understanding of this standard will most likely be able to: Students with a level 4 understanding of this standard will most likely be able to: Identify two-dimensional figures when given a set of attributes. Choose a right triangle. Identify parallel and perpendicular lines in a two-dimensional figure. Identify right, acute, and obtuse angles in a two-dimensional shape. Identify right angles in a right triangle. Classify two-dimensional figures based on the presence or absence of parallel or perpendicular lines. Classify two-dimensional figures based on the presence or absence of angles of a specified size. Recognize right triangles as a category. Identify right triangles and non-right triangles. Classify multiple two-dimensional figures and justify why they can or cannot be grouped together.

Instructional Focus Statements

Level 3:

Students must be able to identify parallel and perpendicular lines as well as types of angles in two-dimensional figures prior to working on classifying figures. Standard 4.G.A.1 is a pre-requisite skill for work on classification. Students learned in grade 3 that shapes in different categories may share attributes and that the shared attributes can define a larger category. This understanding is important for students to have as they use this to classify figures. Instruction at this level should include students sorting and classifying to see how shapes are alike and different. Students should focus on the absence of parallel sides, more than one set of parallel sides, and the presence or absence of varying angle types. Students should see a sufficient variety of examples and need ample opportunities to work with concrete models. Students should be asked to sort and classify shapes when given a specific attribute as well as look at pre-sorted shapes and identify the attribute that was used to classify them. Students should use appropriate academic vocabulary to explain the classifications. Students should be able to classify shapes presented in various ways (i.e., drawings or verbal descriptions).

Right triangles are also a specific focus in this standard. Students should be able to recognize right angles within a right triangle.  They should also be able to identify right triangles and non-right triangles.

Level 4:

Students should classify multiple two-dimensional figures with at least two common attributes and justify why the figures have been grouped or why the figures cannot be grouped together. Venn diagrams, graphic organizers, and Frayer models may be particularly helpful as an organizational tool for students as the classify figures. Students should also have opportunities to make and test conjectures around the attributes for classifying a wide variety of two-dimensional figures. For example, they might consider if an idea is true for all triangles or just specific triangles and explain their reasoning.