Classify shapes and solve geometry problems using what we know of the properties of shapes.

Classifying shapes

In this tutorial, we'll classify two-dimensional figures based on the presence or absence of parallel or perpendicular lines, or the presence or absence of angles of a specified size. We'll also learn about special triangles called "right triangles". Common Core Standard: 4.G.A.2
8:24
Intro to quadrilateral
Sal introduces the term quadrilateral as well as trapezoid, parallelogram, rectangle, rhombus, and square.
5:07
Quadrilateral properties
Sal discusses the properties of quadrilaterals, parallelograms, trapezoids, rhombuses, rectangles, and squares.
5:38
Kites as a geometric shape
Sal discusses a special type of quadrilateral, the kite.
2:49
Quadrilateral types
Sal identifies quadrilaterals as kites, trapezoids, parallelograms, rhombuses, rectangles, and squares.
Exercise
Quadrilateral types
Identify quadrilaterals based on pictures or attributes.  Quadrilaterals included are parallelograms, rhombuses, rectangles, and squares.
6:00
Classifying triangles 1
Sal categorizes triangles as scalene, isosceles, equilateral, acute, right, or obtuse. 
5:30
Classifying triangles by angles
You say you can't categorize a triangle because you don't know the length of the sides. Guess what? If you know the size of the angles you can!
2:23
Classifying triangles 2
Sal categorizes triangles as scalene, isosceles, equilateral, acute, right, or obtuse. 
Exercise
Identify triangles by side lengths
Practice identifying triangles by their side-lengths as equilateral, isosceles, or scalene.
2:15
Classifying shapes by line and angles types
Sal categorizes shapes based on their sides and angles.  
Exercise
Classify shapes by line and angle types
Classify shapes based on pictures or attributes, such as angle types and side-lengths. 
Exercise
Properties of shapes
Identify and compare shapes based on their attributes.  Shapes include triangle types, quadrilateral types, pentagons, and hexagons.
2:28
Classifying quadrilaterals
Sal classifies quadrilaterals by their properties (such as parallel sides).
2:47
Intro to reflective symmetry
Sal introduces the concept of an "axis of symmetry."
Exercise
Identify lines of symmetry and symmetrical figures
Draw and identify lines of symmetry.  Create and identify symmetrical shapes.