Introduction to Plane Figures and Solid Shapes - Visualising Solid Shapes Video Lecture - Class 8

welcome back and in this session I am
going to discuss about I am going to
provide an introduction to the plain
figures and the concept of two
dimensions and solid shape and the
concept of three dimensions so let's get
started so let's first define plane
figure what is a plane figure now when
you say this I mean it gives an idea
that very fundamentally a plane figure
is something which varies only in two
directions when drawn on paper and the
paint figure has only length and breadth
relation this another way of putting it
up now this type of figure which varies
only in two directions when which is
drawn on paper is also called as a
two-dimensional shape now the obvious
examples here are given and the first
one is a rectangle okay now let us try
to see how does it fit into a
declaration of the playing figures now
we say the change occurs where is in two
direction so if we see that if you take
along the width then we have a variation
along this and then if we take along the
height or you can also call the yeah
yeah you can take this as a height or
this is called as the length of this so
basically it is moving in this direction
and it's waiting in this direction okay
so this is a two dimensional shape why
because it is a plane similarly we have
a circle again if you have a look at the
circle there is a variation of this in
this direction and then in this
direction similarly if we have a look at
the triangle it is occupying two
dimensions here so that's why if you can
see that the variation one is in this
direction variation and the other one is
here
okay and then we have our obvious
example which is the square and the
square is also varying in two dimensions
when I say Benny it is it is t you know
it is the direction in which it changes
for example when I start from here I
have told from here to here this is one
splayed direction and then I go again
from here to here so this is the another
direction so we say that this is a two
dimensional shape they are also called
as plane surfaces this is just another
name for it plane surfaces it would also
like to bring to your notice that these
are like very regular variations of
plane figures you could also have in
regular plane figures which is like for
example let's just see a random figure
like this now this figure is also
varying in two dimensions that is this
one and this one these two directions
towards from let's say we can call it
from let's say from the zero towards
this one direction which is we can call
as LV he right one and then towards the
upwards direction so this is what we
mean by plane figures and they also call
as the two dimensional shapes so having
discussed two dimensional shape now let
us try to understand what are the mean
not the solid shapes now if we just have
a look at wave objects around you in
your day to day lines what do you find
out you will find out that most of the
objects they have the apart from length
and breadth you also have that there has
to be perception of depth right so for
example if you for example if you take
your computer or you could take the CPU
will find that it has length breadth and
the
deaf as well right so generally you can
say that solid shapes vary in three
directions and we can also call them
that those three directions could be
length breadth and depth now since they
are wedding in three they're three
directions we call them as
three-dimensional shapes this is another
way of coming it and here are the
examples that you would find in your
day-to-day lives so this one is a
cylinder and I think you will find this
cylinder the most common example of a
cylinder is a gas cylinder that you have
in your votes then we then this is a
sphere the most common example of a
spherical shape is the tennis ball or
any ball that you are using then you
have this structure which is on a cuboid
cuboid then we have a cube in which all
the sides are of equal length we have
this cube then this is another shape
which we have cone the most obvious
thing is an ice cream cone and then we
have this shape is there which is like a
kind of a pyramid structure you can call
it as a tetrahedra so these are the
common examples of three-dimensional
shapes that you will encounter in your
day to day lives and when I say three
dimensions if you see that all these
figures they are giving you a notion of
depth for example you do have variation
in this direction that is one you have
variation in other direction plus you
also are having seeing a variation in
this third direction and hence it is
called a three-dimensional shape so that
was all about the solid shapes now let
us