Perimeter & Circumference (Part - 1) - Circle, Math Video Lecture - Class

hello friends this video on areas
related to circles part 1 is brought to
you by exam fear calm no more fear from
exam we will study circumference of
circle area of sector and area of
combined figures that is this circle
will study how to find circle fans will
study how to find any of sectors and
segments and also will find area of
combined figures here in sector and
segment all solution the first question
that comes to our mind is why should we
study circles you see the tap is be
using our home the bathrooms in the
kitchens
this is in fact most of the pipes are
circle so if you know the area of circle
you can find the volume of water flowing
the speed of water flowing such kind of
thing which you can find if we know
circle if you know circles if you know
how to find perimeter of the circle if
you know how to find the area of the
circle you can find all these things
also if you see the lens we use the
camera lens we use also has the circular
image the lens here this circular if you
see so if you want to find out things in
the camera you can find use it in the
observer also if you see the well which
we use to get water
the bucket is circular change ring is
fully we should use this circular the
well also is circular in most of the
cases so if you see love circular
figures around us the compact this fish
use playing musics series all circular
the ball which you use to play football
and the ball which they be used to play
is all so the tires the types of the car
are circular so if you know circle if
you can find the pavement of a circle
and the area of the circle we should be
studying the slides we can find the
speed of the car
correct so the reason why we are setting
circle is lot of images lot of objects
around us has circular orientation this
thing is circle the ball a circle camera
a circle the white circle in the well it
serve them something do you see around
us the fans you see has a circular thing
of things circular so it's good if we
know circle if you know how to find
parameter of the circle the area of the
circle so now we will study those things
they study the perimeter or
circumference the circle when I say
perimeter of the circle
when I say circumference of the circle
they are saying correct they're a meter
and separates both are same so what is
perimeter so we see this V it took one
eeveelution it is it's tough it from
here
this point it depended and finish at
this point again you see this orange
color correct started from here one
complete evolution and this is nothing
but circumference of the circle
set the pressure circle nothing but you
start from this point you find the
length you go from here here here here
here here then come back to this point
this whole length is nothing but
circumference one parameter on the side
see normal gives me say perimeter of the
square is nothing but you start from
this point you go till this this point
this point you come at this point this
is nothing but perimeter of that square
any object you want to find a perimeter
you start from that object example this
is it you want to find to find the pivot
or the object you start from this point
you here go go go and come back to this
point again that's called parameter of
the object similarly in the case of
circle also then you want to find the
perimeter you start from this point you
go from here to this one I you come back
here and this is your failure it's
usually when I talk about when this time
moves from here to here
in this case if you see the tire moves
from here to here this point is
something which is moving so if you see
this this point itself is moving from it
you see here from here this point is
moving from here D a so this length is
also been emitted from here fine
a tree is also a little don't be
confused now just to understand
parameter is nothing but you start from
one point you go go go go come back to
this point this is called perimeter or
circumference of the circle
both are same typically when you rotate
this tile one revolution on one rotation
is nothing but parameter so if you start
from this point here and if you go and
come back to the same point this point
all each one this is the length of there
and the circumference of perimeter is
defined by the formula PI D D is
diameter pi is nothing but 2 AQ by 7 or
3.14 is a constant value actually every
rational number should be 3.14 it will
continue but we will take the value is
3.14 or 22 by 7 both are same so
circumference for a circle is defined by
PI into D where D is the diameter or we
can also sees her commences nothing but
pi into 2 ry diameter is nothing but 2
times of radius these things you have
learned in the earlier classes circle is
nothing but PI into D so for this circle
this is my diameter this length and call
the sense us see see D is a diameter so
what and this let's suppose o OD is the
radius correct
so circle moon is nothing but PI into D
or PI into 2 1 here pi is irrational
number and it's decimal expansion is non
terminating non-recurring so but we
generally take pi is 22 by 7 or 3.14 as
I told Y is nothing but
do by 7:00 on 3.14 right these
understand circumference is pi into
diameter or by 2 radians boo the same by
is 22 by 7 on 3.9 so one complete
rotation circle makes that is parameter
or in other words we start on point and
you go around come back to the same
point the distance covered is called
perimeter or circumference of God so
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