# K.10 - Geometric Figures

The student will

a)  identify and describe plane figures (circle, triangle, square, and rectangle);

b)  compare the size (smaller, larger) and shape of plane figures (circle, triangle, square, and rectangle); and

c)  describe the location of one object relative to another (above, below, next to) and identify representations of plane figures (circle, triangle, square, and rectangle) regardless of their positions and orientations in space.

### BIG IDEAS

• So that I can find and recognize circles, squares, rectangles, and triangles  in my everyday  life at school and at home and all around me

### UNDERSTANDING THE STANDARD

 An important part of the geometry strand in kindergarten through grade two is the naming and describing of figures. Children move from their own vocabulary and begin to incorporate conventional terminology as the teacher uses geometric terms.Early experiences with comparing, sorting, combining, and subdividing figures assist students in analyzing the characteristics of planefigures.Attribute blocks and tangrams are among the manipulatives that are particularly appropriate for sorting and comparing size and shape.Students should be given opportunities to construct plane figures using multiple tools (e.g., clay, straws, paper, and scissors).Representations of circles, squares, rectangles, and triangles can be found in the students’ environment at school and at home. Students should have opportunities to identify/classify things in their environment by the type of figures those things represent.Presentation of triangles, rectangles, and squares should be made in a variety of spatial orientations so that students are less likely to develop common misconception that triangles, rectangles, and squares must have one side parallel to the bottom of the page on which they are printed.A common misconception students have when a figure such as a square is rotated is they will frequently refer to the rotated square as a diamond.  Clarification needs to be ongoing (e.g., a square is a square regardless of its location in space; there is no plane figure called a diamond).A plane figure is any closed, two-dimensional shape.A vertex is the point at which two or more lines, line segments, or rays meet to form an angle. The term vertices is the plural form of vertex.A polygon is a closed plane figure composed of at least three line segments that do not cross.A triangle is a polygon with three sides.Children should have experiences with different types of triangles (e.g., equilateral, isosceles, scalene, right, acute, obtuse); however, at this level, they are not expected to name the various types.A quadrilateral is a polygon with four sides.A rectangle is a quadrilateral with four right angles.A square is a quadrilateral with four congruent (equal length) sides and four right angles.  At this level, students might describe a square as a special rectangle with four sides of equal length.Students at this level do not need to use the terms polygon, quadrilateral, or congruent.A circle is the set of points in a plane that are the same distance from a point called the center. A circle is not a polygon because it does not have straight sides.

### ESSENTIALS

The student will use problem solving, mathematical communication, mathematical reasoning, connections, and representations to

• Identify a circle, triangle, square, and rectangle. (a)
• Describe the characteristics of triangles, squares, and rectangles, including number of sides and number of vertices. (a)
• Describe a circle using terms such as round and curved. (a)
• Compare and group plane figures (circle, triangle, square, and rectangle) according to their relative sizes (smaller, larger). (b)
• Compare and group plane figures (circle, triangle, square, and rectangle) according to their shapes. (b)
• Distinguish between examples and non-examples of identified plane figures (circle, triangle, square, and rectangle). (b)
• Identify pictorial representations of a circle, triangle, square, and rectangle, regardless of their position and orientation in space. (c)
• Describe the location of one object relative to another, using the terms above, below, and next to. (c)

### KEY VOCABULARY

Updated: Aug 22, 2018