00:01
Hi, we're given here that abcd is a cyclic quadrilateral.
00:13
Abcd is a cyclic quadrilateral and we need to prove here angle b plus angle d is equal to 180.
00:32
We need to prove here angle b plus angle d is equal to 180.
00:37
That's we have right.
00:39
Now we go for the construction here.
00:40
This construction is join a with o and c with o.
00:55
So join a with o and c with o.
01:06
That's we have here.
01:07
Alright.
01:09
So now just going to go towards the proof here.
01:14
So for the proof we have a property here.
01:22
The property is if we have a circle here and we have an arc here.
01:29
Now this arc subtends angle 2x at the center.
01:36
Then it will subtend angle x at the remaining part of circle.
01:44
This property we need to use here.
01:46
So if we take this out it will be angle x this is angle y.
01:51
Right.
01:52
And if you look at this arc here.
01:55
Now this arc subtends angle x at center and angle b at the remaining part.
02:03
So we have angle b will be x over 2...