how do we calculate the area of regular polygons ?

What are regular polygons?
   
Regular polygons are polygons with all sides and all angles equal


Some examples of these are
-Pentagons
-hexagons
-heptagons 


The formula to this :


Area = (½)nas


n = number of sides
a = apothems = length of a side




  
This table shows that the formula is 1/2 times the N(number) of sides, A(apothem) and side length (R)


Example:
   Pentagons - 5 (1/2 x a s)

How do we identify solids ?

First thing we need to know is 


What is a solid ?


A solid is a 3D or three dimensional shape that has a height, width and depth

* There are 2 main types of solids 

     

     - Polyhedra

     - Non - Polyhedra 

Polyhedra 's must have flat faces 

    Examples: Prisms, and Pyramids

Non- Polyhedra's are if any surface isnt flat 

    Examples:

What is isometry ?

An isometry is a transformation where the original figure and its image are congruent.

Types of isometry                    Not a type

        -  Reflection                             -  Dilation 
        -  Rotation   
       -  Translation  

• The reason why dilation isn't a isometry is because the original image is either shrunk or enlarged.

Examples:

    

Reflection

Rotation 

Translation



Practice Question :


What is the type of isometry in the given figure ?

A) Rotation

B) Reflection

C) translation

D) Dilation

Answer : C Translation