What are 2D shapes?
Shapes are shapes with two dimensions “width and height”. 2D shapes are flat and cannot be physically held, because they have no depth.
What is Polygon?
Polygon is a 2-dimensional shape. It is a flat shape with straight sides, and its shape is “closed” (all the lines connect up). A regular shape has all sides the same length and all interior angles the same size. An irregular shape has different lengths sides and/or interior angles.
Here are some examples of 2D Shapes:
Triangle – Square – Kite – Rectangle – Trapezium – Parallelogram – Pentagon – Hexagon – Octagon – Decagon – Nonagon – Rhombus
Circle, oval, and Ellipse are 2D shapes, but are not polygons because they have curves.
What are Regular and Irregular 2D Shapes?
A 2D shape can be classified as regular or irregular based on the length and the interior angles:
-A 2D Regular Shapes:
All sides in 2D shapes are equal in length and all its interior angles measure the same.
-A 2D Irregular Shapes:
All sides in 2D shapes are of unequal length and all its angles are of unequal measures.
Let’s Learn Shapes and Its Properties:
|Circle||A circle has 1 curved side|
A semi-circle has 2 sides; 1 curved side and 1 straight side. The full arc is a 180° angle.
A circle has many parts like circumference, diameter, and radius.
Almost infinite axes of symmetry go through the centre.
Examples of the circle: coins and wheels.
The circumference is the distance once around the circle.
The radius: The distance between the centre of the circle to its circumference is the radius.
The diameter: is a line segment that goes straight across the circle, through the centre. The diameter is always double the radius.
|Oval||An oval has no straight sides and no corners and has 1 face.|
Example of oval: An egg.
|Ellipse||An ellipse is a circle that has been stretched in one direction, to give it the shape of an oval. But not every oval is an ellipse. |
Ellipse has two focal points.
|Triangle||A triangle is a closed shape with 3 sides, 3 vertices and 3 angles. |
It can have up to 2 axes of symmetry.
Example of Triangle: Pyramids and a slice of pizza.
Types of Triangle:
An equilateral triangle is a regular triangle and each angle equals 60°.
A right-angled triangle is any triangle with one right angle.
A scalene triangle is an irregular triangle. All sides and angles are different.
An isosceles triangle has two sides and two angles that are the same.
|Square||A square is a regular quadrilateral and each angle equals 90°. “ all each side are equal “|
It has four axes of symmetry.
Examples of Square: tables and toasts.
|Kite||A kite has two pairs of equal-length sides and the diagonals cross at right angles.||4|
|Rectangle||A rectangle has two pairs of parallel straight lines and each angle equals 90°. |
It has two axes of symmetry.
Examples of rectangles: televisions, whiteboards, and doors.
|Rhombus||A rhombus has two pairs of parallel lines, as well as equal sides and opposite equal angles.|
It has 2 lines of symmetry.
|Trapezium||A trapezium has one pair of parallel lines, and pairs of equal angles. It can have a line of symmetry.||4|
|Parallelogram||A parallelogram has two pairs of parallel lines and opposite equal angles. |
Usually has no axes of symmetry.
|Pentagon||A pentagon has interior and exterior angles. It can be either regular or irregular. |
It can have up to 5 axes of symmetry.
Example of pentagon: The Pentagon building in the US.
|Hexagon||A hexagon has six sides, six vertices and six angles.|
It can have up to 6 axes of symmetry. Hexagon has interior and exterior angles.
Example of a hexagon: Honeycomb cells.
|Heptagon||A heptagon has interior and exterior angles.|
It can be either regular or irregular.
|Octagon||An octagon has interior and exterior angles.|
It can have up to 8 axes of symmetry
Example of an octagon: The stop sign board.
|Nonagon||A nonagon has interior and exterior angles.|
It can be either regular or irregular.
|Decagon||A decagon has interior and exterior angles.||10|
Let’s Draw the 2D Shapes:
What are the 3D shapes?
3D shapes are shapes with three dimensions, width, height and depth. 3D shapes can be physically held.
Properties of 3D Shapes
3D shapes have faces (sides), edges and vertices (corners).
A face is a flat or curved surface with a 3D shape.
An edge is where two faces meet.
A vertex is a corner where edges meet. The plural is vertices.
Types of 3D Shapes:
Sphere – Hemisphere – Cone – Tetrahedron or Triangular based pyramid – Cylinder – Triangular prism – Hexagonal prism – Pentagonal prism – Cube – Cuboid.
|Sphere||A sphere is round in shape. |
It is shaped like a ball and is perfectly symmetrical.
It has a radius, diameter, circumference, volume, and surface area.
Every point on the sphere is at an equal distance from the centre.
|1 Curved surface||–||–|
|Cone||A cone is a 3D shape that has a flat base, and a curved surface. Similar to a cylinder, a cone can also be classified as a right circular cone and an oblique cone.|
A cone is also a rotated triangle.
Example: ice cream.
|Curved surface and 1 face.||1||1|
|Cylinder||A cylinder has a height and a radius. The height of a cylinder is the perpendicular distance between the top and bottom faces.|
The shape stays the same from the base to the top.
A cylinder in which both the circular bases lie on the same line is called a right cylinder.
A cylinder in which one base is placed away from another is called an oblique cylinder.
|2 circular faces, one at the top and one at the bottom, and 1 curved surface.||2||0|
|Hemisphere||A hemisphere has a curved surface area.|
It is not a polyhedron.
A 3D figure is obtained by cutting a sphere in half.
|1 Curved surface and 1 face.||
|Tetrahedron or Triangular -based pyramid||A triangle-based pyramid with equal edges and faces is called a regular tetrahedron.|
A triangle-based pyramid with unequal edges and faces is called an irregular tetrahedron.
A triangle-based pyramid folds out into a large triangle made up of 4 smaller triangles.
|Triangular prism||Its five faces include two triangular bases and three rectangular sides.|
It is a polyhedron congruent and parallel.
|Hexagonal prism||The top and bottom bases are equal to each other in length.|
The diagonals cross the centre point of a regular hexagonal prism.
In a regular hexagonal prism, all the angles of a hexagon are the same.
In an irregular hexagonal prism, all the angles of a hexagon are different.
|Pentagonal prism||The base of a pentagonal prism is in the shape of a pentagon.|
The sides of a pentagonal prism are shaped like a rectangle.
A pentagonal prism is a type of heptahedron, which is a polyhedron with seven plane faces.
A pentagonal prism can also be called a five-sided polygon prism.
The cross-section of a pentagonal prism is a pentagon.
|Cube||Its length, width, and height are the same.||6||12||8|
|Cuboid||Its length, height, and width are different.||6||12||8|
You can mix between some shapes like:
1- The Cone and The Pyramids:
The difference between them is that the cone has a circular base and can roll on its sides.
2- The Cone and The Cylinder :
You can find the difference between them through their rolling point. The circle rolls in a circle, but the cylinder rolls in a straight line.
Let’s Draw “Cube, Cylinder and Cuboid”:
Let’s Know the Difference between 2D and 3D Shapes:
2D means (Two Dimensional) length and width. 2D figures are plane shapes. They have areas but not volume. Straight lines make up the sides of the 2D shapes. They are drawn using X-axes, and Y-axes. 2D shapes are used to give a simple view of an object. All edges of 2D shapes are visible. It is easy to draw and explain details in 2D shapes. It is easy to draw 2D Shapes.
For Example Circle, oval, triangle, etc.
3D means (Three Dimensional) length, width, and height or depth. 3D shapes do have areas and volume. 3D shapes are drawn using X-axes, Y-axes, and Z-axes. 3D shapes are used to give an architectural view of an object. In 3D shapes, some of the edges are hidden. In 3D shapes, only outer dimensions can be explained. The details become difficult in 3d shapes. 3D shapes are complex in the drawing.
For Example sphere, cube, cuboid, etc.