Can you name the shapes of these objects?
The first is a triangle. The coin is a circle, and the chessboard is a square.
These are examples of two-dimensional shapes!
Can you see how the square is different from the cube? 🤔
✅ The square has length and width, but no depth.
A square can lie flat on a surface.
2D Shapes are flat. They only have two measurements - length and width. This is why they're called two-dimensional, or 2D!
Some other examples of 2D shapes are circles, triangles and rectangles.
😎 Most 2D shapes are made up of lines and corners. These parts of a shape have special names.
- The line segments that make a 2D shape are called its sides.
- A corner at which two sides of a 2D shape meet is called a vertex. Two or more corners are called vertices (not vertexes!).
- A measure of the turn between the two sides that meet at a vertex is called the angle between the sides.
Different 2D shapes have different numbers of sides. 🤓
Let's learn about the most common 2D shapes.
A triangle is made up of 3 sides. These sides may or may not be equal.
It has 3 vertices and 3 angles.
A rectangle has 4 sides, 4 vertices and 4 right angles (90° angles).
Opposite sides of a rectangle are equal and parallel to each other.
🤓 Tip: The word quadrilateral means a 4 sided shape. Rectangles are quadrilaterals.
A square is a special type of rectangle, in which all 4 sides are equal.
Like a rectangle, a square also has 4 vertices, 4 right angles, and parallel opposite sides.
A rhombus looks like a diamond, or a lopsided square.
Like a square, a rhombus also has 4 equal sides and 4 vertices.
Opposite sides of a rhombus are parallel to each other.
Opposite angles of a rhombus are equal to each other.
Tip: A square is a rhombus. But not all rhombuses are squares!
A trapezoid also has 4 sides, 4 vertices and 4 angles.
A trapezoid is 4-sided shape with only 1 pair of parallel sides.
So squares and rectangles are not trapezoids.👍
A pentagon has 5 equal sides, 5 vertices and 5 equal angles.
A hexagon has 6 equal sides, 6 vertices and 6 equal angles.
An octagon has 8 equal sides, 8 vertices and 8 equal angles.
A circle is a round shape that has no sides or vertices.
The distance from the center of a circle to any point on its boundary always remains the same.
Great job learning about two-dimensional shapes! 👏
Now, complete the practice to help you remember for longer. 💪