##### Chapter 4

## Geometry

The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:

#### Introduction

Angles are classified into five categories depending on their direction. These five kinds of angles are the most popular in geometry:

- Acute Angles: An acute angle is one that sits between 0 and 90 °, or in other terms, one that is less than 90 °.
- Obtuse Angles: The inverse of an acute angle is an obtuse angle. An obtuse angle is one that is greater than 90 ° but less than 180 °, or in other terms, one that is greater than 90 ° but less than 180 °.
- Right Angles: A 90-degree angle is often a right angle.
- Straight Angles: As examined, a straight angle is 180 °.
- Reflex Angles: A reflex angle is any angle that is > than 180 ° but < than 360 ° (which is the same as 0 °).

The following are examples of quadrilaterals:

- Convex: A quadrilateral’s diagonals are both entirely embedded inside a figure.
- Concave: A quadrilateral that has at least one diagonal that is partially or completely outside of the figure.
- Intersecting: Intersecting quadrilaterals are not the same as plain quadrilaterals with non-adjacent sides intersecting. Self-intersecting or crossed quadrilaterals are examples of this kind of quadrilateral.

A line segment is bounded by two distinct points on a line in geometry. A line segment is a section of a line that links two lines. A line has no endpoints and may stretch in all directions indefinitely, while a line section has two fixed or definite endpoints.

A line segment may be measured by different methods which are:

- Method of observation
- Method using trace paper
- Method using ruler and divider

An angle is formed by two rays of the same endpoint. The vertex is the place where the two converge. The angle is a component of a hypothetical circle. There are four different kinds of angles. Knowing the discrepancy will help you approximate the angle measurement.

- Acute Angle
- Straight Angle
- Right Angle
- Obtuse Angle

A protractor is a perfect tool for measuring angles. Begin by aligning one ray with the protractor’s 0-degree axis. Then, align the vertex with the protractor’s midpoint. To find the angle’s measurement to the nearest degree, follow the second light.

A circle is a two-dimensional figure which is closed and all its points in the plane are at equal distances from a single point known as the “centre.” The line of reflection symmetry is formed for any line that moves around the circle. For any angle, it often has symmetry (rotational) around the middle.

- Place a single point on an empty sheet of paper, somewhere in the centre of the sheet, and mark it as point A.
- Choose a random distance for the radius, such as 5 cm.
- Hold the reference zero mark on point A and mark 5 cm away from point A in both directions with a ruler.
- Mark as many points as you like away from point A, but they must all be within 5 cm of point O.
- If you choose enough points, you’ll find that the form begins to imitate a circle.

In geometry, students think about various geometrical forms, how they are constructed, and how to calculate them. Shapes may have a line of symmetry, regardless of whether they are geometrical or non-geometrical.

The hypothetical line that divides a figure into two parts that are mirror reflections of each other is called the line of symmetry. That is, they are precisely splitting the image into two equal bits. Those two sections are the same size and shape as another component.

In conclusion, geometry is angles, measurements, and proportions of a wide range of objects. There are five kinds of angles which are Acute Angles, Obtuse Angles, Right Angles, Straight Angles and Reflex Angles. A line segment is measured by method of observation, method using trace paper, method using ruler and divider.

**What are some of the fundamentals of geometry?**Three fundamental geometrical principles underpin all other geometrical concepts. The point, line, and plane are the three fundamentals.

**Who was the first to invent geometry?**Euclid was a brilliant mathematician who was named the “Father of Geometry” by many.

**What is the concept of geometry?**Geometry is a field of mathematics that explores how objects are measured in terms of their proportions, forms, angles, and dimensions. 2D forms are simple shapes such as squares, rings, and triangles that are part of flat geometry.

**What role does geometry play in nature?**Geometry helps us in deciding what materials to use, what design to make and also plays a vital role in the construction process itself.**What is the most powerful shape?**

The triangle is a geometrical shape. The triangle is the most powerful formation, it is able to maintain its shape and provide a solid foundation.