Geometry
Geometry is a branch in mathematics which deals with all the shapes and their properties. It can be divided into two types:
- Plane Geometry.
- Solid Geometry.
Plane Geometry
![](https://www.earthslab.com/wp-content/uploads/2019/01/Untitled-3.jpg)
Plane geometry is all about flat shapes circles, lines, triangles etc. All the shapes that can be drawn on paper.
Solid Geometry
![](https://www.earthslab.com/wp-content/uploads/2019/01/geom37-1024x263.jpg)
Solid geometry deals with 3D (three dimensional) objects. For example: cube, prism, cylinder etc.
What is a Point, Line and a Ray?
Point: It is defined as a particular or precise location on a piece of paper or a plane surface, represented by a dot.
Line: A line can be said a combination of infinite points together. It extends in both the directions.
Ray: When a line has starting point and no end point it is called as ray.
Angle
Angle is a figure formed by two lines or rays, sharing a common end point (vertex).
Types of angles:
- Acute angle.
- Right angle.
- Obtuse angle.
- Straight angle.
- Reflex angle.
- Full angle.
Acute Angle
![](https://www.earthslab.com/wp-content/uploads/2019/01/1450397-200.png)
Angle smaller than 90⁰ is called acute angle. It ranges from 0⁰ - 90⁰.
Right Angle
![](https://www.earthslab.com/wp-content/uploads/2019/01/851aadfe97aa5c16390b2942878e97b4.png)
An angle of 90⁰.
Obtuse Angle
![](https://www.earthslab.com/wp-content/uploads/2019/01/649781-200.png)
Angle greater than 90⁰ but lesser than 180⁰ is called an obtuse angle. It ranges from 90⁰ - 180⁰.
Straight Angle
![](https://www.earthslab.com/wp-content/uploads/2019/01/180-degree-straight-angle.png)
An angle of 180 is called straight angle. It is formed by a straight line.
Reflex Angle
![](https://www.earthslab.com/wp-content/uploads/2019/01/1450460-200.png)
Angle greater than 180⁰ but lesser than 360⁰ is called a reflex angle.
Full Angle
![](https://www.earthslab.com/wp-content/uploads/2019/01/2000px-Full_angle.svg-1024x539.png)
An angle which has an exact measure of 360⁰ is called full angle.