00:01
So this is the given question.
00:02
We are asked to find the surface, sorry, perimeter in the area of the given figure.
00:09
So the given figure consists of three parts.
00:12
Suppose this is part one, this is part two, and this is part three.
00:18
It is given that part one and three is made up of semi -circles and part two is of one -fourth of a circle, that means quarter circle.
00:29
Now before entering into the problem, we have to know some basic formulas.
00:36
That is, suppose if this is a circle, if this is a circle or just a minute, this is a circle with radius r, with a radius r, the perimeter of the circle, the perimeter of the circle, perimeter p of a circle is equal to 2 pi r, okay, and area of a circle, area equal to pi r square now with the help of this we can do the given question now i am representing first one we have to find is the perimeter of the set of this figure okay perimeter is nothing but length of all sides or since this is a curve the length of the curve is nothing but the perimeter so this perimeter also consists of three parts the first one is just a minute the first one is same drawing due to this semicircle see so this is first part and this is third part.
01:39
They both are identical.
01:41
So i am drawing with them with the same color.
01:44
Now, and also this one.
01:49
See this black one i am drawing.
01:51
This is the second part.
01:52
So we have to find the length of one, two and three, these three curves and we have to add them up.
02:00
Then we get the perimeter of the circle.
02:03
Therefore, perimeter equal to, sorry, and one thing.
02:06
Before doing that we have to find the radius of these three circles.
02:11
So this is the semicircle, the first one.
02:14
So since this is semicircle, the center will be somewhere here for both of these two.
02:20
So this length 8 meters is the diameter for 1.
02:24
Therefore, for 1 and 3, for parts 1 and 3, diameter, diameter d equal to 8 meters, and radius.
02:37
And radius r is equal to diameter by 2 that is 8 by 2 that is 4 meters okay now for part 2 for part 2 this is the center see so this is nothing but the radius so radius is nothing but r2 equal to 8 meters okay for part 1 and 3 diameter and radius are same because both are same for part 2 the radius is 8 meters now with the help of this, let us try to solve this problem.
03:13
Therefore, perimeter of this figure, perimeter of this figure equal to perimeter of 1 plus perimeter of 2 plus perimeter of 3.
03:24
Okay, since 1 is a semicircle, the perimeter of circle is 2 pi r.
03:29
So the perimeter of this semicircle is, since semi -circle is half of the circle, the perimeter would also be half...