# Most Powerful Guide on Major Types of Geometry You Should Know As we all in our student life study about geometrical shapes, formulas, and concepts. But at that time, we do not focus on the types of geometry; we just know how to calculate the area of the circle, determine the volume of a cuboid, etc.

We all know geometry is a complex area of mathematics. This is because we need to learn a large range of formulas regarding different objects and shapes, and we need to think logically while applying the formulas.

We get perplexed when we study about the different types of geometry and areas or concepts they cover.

So, let’s explore major geometry types along with other concepts.

## What is geometry?

Geometry word comes from the Greek word ‘geo’ (earth) and metric(measurement). So geometry means ‘earth measurement’.

It is a wide branch of mathematics that deals with the study of shapes, size, dimensions, etc., of space.

## Major types of Geometry?

Geometry is categorized in Euclidean and non-Euclidean geometry.

Euclidean Geometry consists of plain, solid, and spherical geometry.

Non-Euclidean geometry involves hyperbolic and elliptic geometry.

Here we will discuss Euclidean Geometry.

There are three major types of  Euclidean geometry.

Plane Geometry

Solid Geometry

Spherical Geometry

### Plane Geometry

It is also known as 2-D geometry as it works on 2-D flat shapes, which can be drawn on paper such as circles, triangles, squares, semicircles, etc. In this type of geometry, we include the length and breadth of the shapes and avoid the depth.

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Terminology of Plane Geometry-

### Point

A dot represents a point, and it is a place on the plane. A point is dimensionless, but it has a position. We consider the point as a place rather than a thing.

### Line

A line combines infinite points, endless, straight, with no thickness, and can be extended to infinity. In geometry, we take the horizontal line as the x-axis and the vertical line as the y-axis.

### Line Segment

It is a part of a line. When we have a line with a starting and ending point it is called a line segment.

Line segment

### Ray

A line with a starting point but not ending point is known as rays such as Sun rays.

### Geometric  Angles

An angle is a formation of two rays. When two rays cut each other they make an angle and share the common endpoint(vertex) of rays.

### Acute Angle

An angle that can vary between 0 and 90 degrees is called an acute angle. In simple words you can say an angle that is smaller than a right angle(90 degree) is known as sharp(acute angle)

Obtuse Angle– An angle which is more than a right angle(90 degree) is an obtuse angle. It should be less than 180 degrees.

Right Angle- A right angle has the value of 90 degree.

Straight Angle- An angle formed by a straight line is a straight angle. It is at an angle of 180 degrees.

## Plane Figures in Geometry-

Polygons- Polygons are closed plane figures in geometry. As the name suggests poly(multi) gons(sides) are figures of multiple sides. For example a triangle is a figure of three sides, a rectangle is a figure of four sides.

Sum of internal angles of a polygon= (n-2)х180

Each interior angle= sum of internal angles/sides

Where n is the number of sides.

Suppose we need to calculate the sum of the internal angle of a pentagon.

Apply the formula

Here n=5

(5-2).180

3.180=540 degrees is the sum of the internal angle of a pentagon.

Each interior angle= 540/5=108

## Different types of polygon

• Triangles( 3 sides)
• Pentagon( 5 sides)
• Hexagon( 6 sides)
• Heptagon( 7 sides)
• Octagon (8 sides)
• Nonagon (9 sides)
• Decagon (10 sides)

### Triangle

sides=3

Sum of internal angles= 180 degrees.

Types-

Equilateral Triangle- It has 3 equal sides and each angle is of 60 degree.

Isosceles Triangle- It has two sides and angle equals.

Sides=4

Sum of internal angles=360 degrees

Types-

Square-It  has 4 equal sides and vertices at right angles.

Rectangle-It has opposite sides equal and all angles are of 90 degrees.

Parallelogram-It has two pairs of parallel sides where opposite sides and angles are equal.

Rhombus-It has all the four sides to be of equal length but their internal angles are not of 90 degrees.

Trapezium- It has one pair of opposite sides which are parallel to each other.

### Pentagon

sides= 5

Sum of internal angles= 540 degrees.

### Hexagon

It has six straight sides and angles.

sides=6

Sum of internal angels=720 degrees.

### Heptagon

It is a plane figure with seven sides and seven angles.

Sum of internal angles=900 degrees.

### Octagon

It has eight sides and eight angles.

Sum of internal angles= 1080 degrees.

### Nonagon

It has 9 sides and 9 angels.

Sum of internal angles=1260 degrees

### Decagon

It has 10 sides and 10 angles

Sum of internal angles=1440

## Circle in Geometry

When we talk about plane types of geometry, it includes circles with the other shapes.

A circle is a closed curved shape from the center point. It consists of radius, diameter, chord etc.

Similarity of circle- Same shape or have an equal angle, but the size is different.

Congruence of circle-Same shape and size.

## Solid Geometry

It covers the study of 3-D (dimensional) shapes such as cubes, cylinders, spheres. Solid geometry includes three dimensions of shapes like length, breadth, and height.

It is one of the comlex types of geometry.

Our surrounding objects are three dimensional. Faces, edges, vertices are some features of 3-D shapes. Let’s discuss them one by one.

### Edges

These are the line segments that join one vertex to the other. In simple words, these are the faces that meet in the straight line. Different shapes have different edges.

For example, a cube has 12 edges, a square pyramid has 8 edges.

### Faces

A face is a flat surface that is enclosed by the edges. The face should be a 2-D figure for a 3-D shape.

A cube has 6 faces and a square pyramid has 5 faces.

### Vertices

Where the edges of any 3-D shape meet at each other is defined as a vertex. It is the point where the adjacent sides of the polygon meet.

A cube has 8 vertices and a triangular pyramid has 4 vertices.

### Spherical Geometry

It studies the 2-D surface of a sphere. The terms like a ball or other sphere objects are used for the surface and the 3-D interior, but in this context, the word sphere is used for the 2-D surface.

## Conclusion

I hope now you are familiar with the types of geometry. Geometry is a vast area to cover as it belongs to different 2-D and 3-D shapes with their measurements.

This blog has covered the major geometry types that will help you understand geometrical concepts. If you want to be a master of geometry, you need to strengthen your basic concepts and logical thinking. Get the best online geometry homework help from the experts and enjoy high grades.