I did not understand the video please explain it to me as soon as possible - Maths - The Triangle and its Properties

Question

I did not understand the video please explain it to me as soon
as possible

Mayank Bhardwaj · Accepted Answer

Hi Rishabh!
The video represents the proof of the angle sum property of a
triangle
I have explained it again Just go through it
Consider the âˆ†PQR, let ∠1, ∠2,
∠3 be its interior angles
To prove angle sum property of any triangle it is required to
prove ∠1 + ∠2 + ∠3 = 180°
For this extend QP to same point Also draw a ray through P
that is parallel to QR
<img src=
"https://s3mn%20mnimgs%20com/img/shared/userimages/mn_images/image/sum3%20png"
style="width: 344px; height: 153px;" alt="">
Now, PX||QR
∴ ∠5 = ∠3 (alternate interior angle)
(1)
∠6 = ∠2 (corresponding angles) (2)
SPQ is a line segment PX ray and PR segments stand at point P
on it
∠6 + ∠5 + ∠1= 180°
⇒ ∠2 + ∠3 + ∠1 = 180° [Using (1),
(2)]
⇒ ∠1 + ∠2 + ∠3 = 180°
This shows that the sum of interior angles
âˆ†PQR is 180°
This is true for any triangle This is called angle sum
property of a triangle
Hope! This will help you to understand the concept If you face
some problem, write the specific step (s) so that we can provide
you meaningful help
Cheers!!!

I did not understand the video. please explain it to me as soon as possible.