Explore properties of 2D shapes including sides, angles, and symmetry using art gallery scenarios!
Scenario: You're visiting an art gallery with paintings of different shapes. The curator wants you to help organize the artwork by identifying the properties of each shape. Can you help classify the shapes based on their sides, angles, and symmetry?
2D (two-dimensional) shapes are flat shapes that have length and width but no depth. They exist on a flat surface like a piece of paper or a computer screen.
Square
Rectangle
Diamond
Circle
Every 2D shape has sides, angles, and may have symmetry
Windows, doors, paintings, and many everyday objects
The sides of a shape are the straight lines that form its boundary. Vertices (plural of vertex) are the points where two sides meet.
Triangle: 3 sides, 3 vertices
The simplest polygon
Square: 4 sides, 4 vertices
All sides equal, all angles 90°
Pentagon: 5 sides, 5 vertices
Five-sided polygon
Angles are formed where two sides meet. We can classify angles by their size:
Right Angle: 90° (like a corner of a square)
Forms a perfect L-shape
Acute Angle: Less than 90°
Sharp and narrow
Obtuse Angle: More than 90°
Wide and open
A shape has symmetry if you can draw a line through it and both sides are mirror images of each other. This line is called a line of symmetry.
Square: 4 lines of symmetry
Vertical, horizontal, and two diagonal lines
Rectangle: 2 lines of symmetry
Vertical and horizontal lines only
Circle: Infinite lines of symmetry
Any line through the center
Look at these shapes in the art gallery. Classify each one by its properties:
Shape A: 4 equal sides, 4 right angles
Square
4 lines of symmetry
Shape B: 3 sides, 3 acute angles
Acute Triangle
0-3 lines of symmetry
How many lines of symmetry does each shape have?
Regular Pentagon
5 lines of symmetry
Regular Hexagon
6 lines of symmetry
Isosceles Triangle
1 line of symmetry