Subscribe to our YouTube channel for the latest videos, updates, and tips.


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.

Measuring Ruler

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. 

Set-Squares

In one, the angles are 30°, 90°, 60° and in the other, the angles are 45°, 45°, 90°.


III: Protractor:

Semicircular 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. 

Compass

It is used to mark off equal lengths, but does not measure them. It is also used to draw arcs and circles.


V: Divider:

Divider

A divider has a pair of pointers. It is used to compare lengths.

You might like these



7th Grade Math Problems 

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.



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.




Share this page: What’s this?

Recent Articles

  1. Calculating Profit Percent and Loss Percent | Profit and Loss Formulas

    Jun 12, 25 12:48 PM

    In calculating profit percent and loss percent we will learn about the basic concepts of profit and loss. We will recall facts and formula while calculating profit percent and loss percent. Now we wil

    Read More

  2. Word Problems on Profit and Loss Worksheet |Cost Price |Selling Price

    Jun 11, 25 04:26 PM

    Word Problems on Profit and Loss Worksheet
    In word problems on profit and loss worksheet you will get different types of problems on cost price and selling price, profit and loss, calculating profit o loss, calculating selling price and cost p…

    Read More

  3. Round off to Nearest 1000 |Rounding Numbers to Nearest Thousand| Rules

    Jun 11, 25 03:12 PM

    Round off to Nearest 1000
    Round off to nearest 1000 is discussed here. While rounding off to the nearest 1000, if the digit in the hundreds place is between 0 – 4 i.e., < 5, then the hundreds place is replaced by ‘0’. If the d…

    Read More

  4. Round off to Nearest 100 | Rounding Numbers To Nearest Hundred | Rules

    Jun 11, 25 03:13 AM

    Round off to Nearest 100
    While rounding off to the nearest hundred, if the digit in the tens place is between 0 – 4 i.e. < 5, then the tens place is replaced by ‘0’. If the digit in the units place is equal to or >5, then the…

    Read More

  5. Round off to Nearest 10 |How To Round off to Nearest 10?|Rounding Rule

    Jun 10, 25 05:36 PM

    Rounding to the Nearest 10
    Round off to nearest 10 is discussed here. Rounding can be done for every place-value of number. To round off a number to the nearest tens, we round off to the nearest multiple of ten. A large number…

    Read More