What is Geometry

What is Geometry?

Geometry is the branch of mathematics concerned with the properties and relations of points, lines, surfaces, solids, and higher dimensional analogs.

Geometry arose independently in a number of early cultures as a practical way for dealing with lengths, areas, and volumes.

Geometry is all about shapes and their properties. If you like playing with objects, or like drawing, then geometry is for you! Geometry goes from points, lines and planes to triangles, polygons, and angles.

Why do we do Geometry?

To discover patterns, find areas, volumes, lengths and angles, and better understand the world around us.

2D Shapes

When a shape has only a length and width then it is a two-dimensional shape. 2D shapes are flat and they can be cut out on a piece of paper. They have sides, vertexes, and interior angles. This does not include a circle because it is one continuous loop. Polygons are 2D shapes and have at least 3 straight sides.

Basic 2D shapes include: Triangles, Circles, Quadrilateral, and polygons

Other 2D shapes include: Pentagon, Hexagon, Heptagon, Octagon, Nonagon, Decagon, Hendecagon, Dodecagon

Angles

Angles are formed when two lines meet at a shared point. A full circle has a measure of 360 degrees. A triangle has a measure of 180 degrees. A straight line also has a measure or 180 degrees. Each shape has a different degree measure by this equation: (n-2)180, n equals the number of sides that the shape has. They are measured in degrees and there are three types of angles.

The different angles include: obtuse angles, right angles, and acute angles.

Obtuse angle is when the angle measurement is greater than 90 degrees. A right angle is when the angle measurement is 90 degrees. Lastly, an acute angle is an angle measurement less than 90 degrees.

3D shapes

A 3D shapes is and object or solid that has a height, length, and width. 3D objects have a surface are, which measure the area outside of the object, and volume, which measure the space inside the solid. A 3D object is most likely something you use in your everyday life!

Some 3D object include: Cube, Cone, Cuboid, Triangle-based Pyramid, Square-based Pyramid, Prism, Cylinder, and Sphere.

Symmetry

A symmetrical shape can be split in two down the line of symmetry. This can be a dotted line you can draw down the middle of a shape to show two equal halves. this type of symmetry is called reflexive symmetry. A shape can also have rotational symmetry, where you can rotate the shape and it still exactly fits into its own outline. A shape that is not symmetrical is referred to as asymmetrical.