Practical Geometry
We have learnt the technique of measuring line segments and comparing two line segments by observation, by tracing and by using a divider.
In practical geometry, we study geometrical constructions.
The word 'construction' in geometry is used for drawing a correct and accurate figure from the given measurements. In this chapter, we shall learn how to draw some plane figures using the instruments; ruler, set-square, protractor, compass.
Let us first know something about these geometrical instruments.
I: Ruler/Straight-Edge/Scale:
The straight-edge is graduated into centimeters along one edge and inches along the other edge.
It is used to draw line segments and measure their length.
II: Set-Squares:
A pair of set-squares has two instruments (triangular in shape) in the geometry-box.
In one, the angles are 30°, 90°, 60° and in the other, the angles are 45°, 45°, 90°.
III: Protractor:
To measure the number of degrees in an angle, an instrument called protractor is used.
It is graduated into 180 equal divisions; each division represents one unit measure of an angle, called a degree. Thus, the protractor is marked from 0 degree up to 180 degrees (i.e. 0° to 180°) in both directions and the straight edge of the protractor lies along the line segment joining the 0° mark and 180° mark.
IV: Compass:
A compass has a pointer (i.e. metal-end) on one end and a pencil holder on the other.
It is used to mark off equal lengths, but does not measure them. It is also used to draw arcs and circles.
V: Divider:
A divider has a pair of pointers. It is used to compare lengths.
You might like these
Quadrilateral | Angle Sum Property of a Quadrilateral | Adjacent Sides
What is quadrilateral? A simple closed figure formed by joining four line segments is called a quadrilateral. It has 4 sides, 4 angles, 4 vertices and two diagonals.
Quadrilateral Worksheet |Different Types of Questions in Quadrilateral
In math practice test on quadrilateral worksheet we will practice different types of questions in quadrilateral. Students can practice the questions of quadrilateral worksheet before the examinations
Fundamental Geometrical Concepts | Point | Line | Properties of Lines
The fundamental geometrical concepts depend on three basic concepts — point, line and plane. The terms cannot be precisely defined. However, the meanings of these terms are explained through examples.
Angles | Magnitude of an Angle | Measure of an angle | Working Rules
Angles are very important in our daily life so it’s very necessary to understand about angle. Two rays meeting at a common endpoint form an angle. In the adjoining figure, two rays AB and BC are calle
Regular and Irregular Polygons | Definitions |Examples|Questions & Ans
We will learn about different types of regular and irregular polygons and their properties. Regular polygon: A polygon which has all its sides of equal length and all its angles of equal measures
Construction of a Circle | Working Rules | Step-by-step Explanation |
Construction of a Circle when the length of its Radius is given. Working Rules | Step I: Open the compass such that its pointer be put on initial point (i.e. O) of ruler / scale and the pencil-end be put on a mark say 4 cm (Let the radius of the circle be 4 cm).
8th Grade Math Practice
From Practical Geometry to HOME PAGE
Didn't find what you were looking for? Or want to know more information about Math Only Math. Use this Google Search to find what you need.
Recent Articles
-
Quarter Past and Quarter To | Quarter Past Hour | Quarter to Next Hour
Nov 23, 24 03:45 PM
The hands of clock move from left to right. This is called the clock wise motion. When the minute hand is on the right side of the clock, it shows the number of minutes past the hour. When the minute… -
Half Past an Hour | What does Half Past Mean? | Half an Hour|Half Past
Nov 23, 24 03:14 PM
We learnt that, one hour is equal to 60 minutes. When one hour is divided into two, it is half an hour or 30 minutes. The minute hand points at 6. We say, 30 minutes past an hour or half past an hour… -
Telling the Time | Teaching Time | Analogue Clock| Reading Time
Nov 23, 24 02:51 PM
Teaching time is an interactive activity for telling time. This activity helps students to learn how to read the clock to tell time using the analogue clock. While reading or observing the time on a -
2nd Grade Fractions Worksheet | Basic Concept of Fractions | Answers
Nov 23, 24 12:22 AM
In 2nd Grade Fractions Worksheet we will solve different types of problems on fractions, one-whole, one-half, one-third, one-fourth, three-fourth or s quarter. In a fraction, it is important that the… -
Time Duration |How to Calculate the Time Duration (in Hours & Minutes)
Nov 22, 24 12:34 AM
Time duration tells us how long it takes for an activity to complete. We will learn how to calculate the time duration in minutes and in hours. Time Duration (in minutes) Ron and Clara play badminton…
New! Comments
Have your say about what you just read! Leave me a comment in the box below. Ask a Question or Answer a Question.