What is a Pentagon in Geometry

Introduction to Pentagon in geometry:

Pentagon is the one of the important mathematical figure in geometry.  It is a five sided polygon.  Pentagon is making with the help of 5 sides and 5 angles. Pentagon is classified into following two types.  They are

Regular Pentagon
Irregular pentagon
In this article we have to study about what is pentagon in geometry.


Brief Study about what is a pentagon in geometry?


What is Regular pentagon in geometry?

A pentagon is usually 5 sided figures.  The sides and angles are equal of the pentagon are equal in measure so it is named as regular pentagon.

What is Irregular pentagon in geometry?

Irregular pentagon is also one of the types of pentagon.  Here the sides and angles are not equal in measure.  They are different sides and angles.  So it is named as irregular pentagon.

What is the Pictorial representation of the Regular Pentagon?

What are the Properties of the regular pentagon?

5 sides are equal in measure
5 angles are equal in measure.
Sum of the interior angles measures 540 degree
Each interior angle measures 108 degree
Sum of the exterior angles measures 360 degree
Exterior angle measures 72 degree
Pentagon is formed with the help of three triangles
Pentagon has five lines of reflectional symmetry
Pentagon has five lines of rotational symmetry

What is the area of the regular and irregular pentagon?

The following formula is used to find the area of the regular pentagon,

A=`(1)/(2)` x Apothem X Perimeter

Here A is the area of the pentagon

Apothegm is the radius of the in circle of the pentagon

Perimeter is the sum of all sides of the pentagon

This is the formula to calculate the area of the pentagon.

Geometry Proportions

Introduction of geometry proportions:-

In mathematics, Proportions in arithmetic and geometry, a particular relation between groups of numbers or quantities. In arithmetic, proportions are the equality of ratios; ratio is the division of one number by another. A continued proportions is a property of every three terms in a geometric progression. A proportions is a statement that two ratios are equal such as a:b = c:d.



Example problem for geometry proportions:-


Problem1:

Are the ratios 30g: 40g and 48 kg: 72 kg in geometry proportions?

Solution:

30 g: 40 g =30 / 40 = 3 / 4

= 3: 4

48 kg: 72 kg = 48 / 72 = 4 / 6

= 4: 6           So, 30: 40 = 48: 72.

Therefore, the ratios 30 g: 40 g and 48 kg: 72 kg are in geometry proportions,

i.e. 30 : 40 :: 48 : 72.

The middle terms in this are 40, 48 and the extreme terms are 30, 72.


Problem 2:

Do the ratios 30 cm to 4 m and 20 sec to 5 minutes form a geometry proportions?

Solution:

Ratio of 30 cm to 4 m = 30: 4 × 100 (1 m = 100 cm)

= 3: 40

Ratio of 20 sec to 5 min = 20: 5 × 60 (1 min = 60 sec)

= 20: 300

= 1:15

Since, 3: 40 ≠ 1: 15, therefore, the given ratios do not form a geometry proportions.



Problem 3:

Sam works as a dental hygienist. Last week Sam ade 500 for 20 hours of work How many hours must Sam work in order to make 800?

Solution:

Sam works as a dental hygienist

50020hours=800 / x hours

20 hours * $800 = x hours * $500

16000 = $500 x

16000 / 500 = x

32 = x

Sam 32 hours work in order to make $800

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Practice problems for Geometry proportions problems:        


Problem 1:

Gabriella bought five cantaloupes for 3 How many can taloupes can Shayna buy if she has21?

Answer: 35 gabriella

Problem 2:

If you can buy one can of pineapple chunks for 5 then how many can you buy with 10 ?

Answer: 50 pineapple chunks

Problem 3:

If you can buy four bulbs of elephant garlic for 12 then how many can you buy with 96?

Answer:  8 bulbs

Problem 4:

One package of blueberries costs 6 How many packages of blueberries can you buy for 42?

Answer: 7 blueberries

Geometry Sample Test

Introduction to Geometry sample test:

Geometry is the method  of finding  the volume or  dimension of an object. Buildings, cars are some examples of geometry. Geometry sample test help students in finding the area, perimeter, circumference of  Two-dimensional figures like triangle, circle, rectangle, rhombus, trapezoid, quadrilateral etc.Geometry  sample test problems are used in real life situations such as how much water can we store in a tank. Here lot of geometry sample test questions are given with answers for our practice.


Geometry sample test:


Example 1:

Find the perimeter of square whose sides are 17 cm.

Solution:

given the side if square is 17 cm

Perimeter of the square, P = 4a

= 4 × 17 cm

=  68 cm

Hence the perimeter of square is 68 cm.

Example 2:

Find the volume of right cylinder that has radius 5 cm and height 12 cm.

Solution:

Given, r = 5 cm

h= 12 cm

Volume of circular cylinder = pi * r2 * h cu. Units

= `(22/7)` * 5 * 5 * 12 = 942

Volume of circular cylinder = 942 cm^2

I have recently faced lot of problem while learning arc length of a circle, But thank to online resources of math which helped me to learn myself easily on net.

Geometry sample test:


Example 3:

The perimeter of the floor of a square room is 35m. Find the area of the floor of given perimeter.

Solution :

To find the area of a given square of perimeter 35 m, we need to measure its side. Here perimeter of the square is given, we
need to find the side of square from its perimeter.

Perimeter of square ground, p = 4a

4a = p

a = p/4

Hence, a = 35 / 4 m [since p = 22 m ]

∴ a = 8.75 m

Area of the square ground A = a2

= 8.75 m × 8.75 m

i.e. Area = 76.5625 sq.m.

Example 4:

Find the volume of the right prism whose area of the base is 450 cm^2 and height is 28cm

Solution:

Given that area of the base, A = 540 cm^2 and height (h) of the prism = 13 cm

Volume of the right prism = area of the base * height cu.units

= A * h

= 540⋅13

Volume of right prism = 7020 cm3