Here, ∠P+ ∠Q 180° [Sum of co-interior angles is 180°]
⇒ ∠P+130°=180°
⇒ ∠P=180°-130°
⇒ ∠P=50°
∵ ∠R=90° [Given]
∴ ∠S+90°=180°
⇒ ∠S=180°-90°
⇒ ∠S= 90°

Yes, one more method is there to find ∠P.
∠s + ∠R + ∠Q+ ∠P=360° [Angle sum property of quadrilateral]
⇒ 90°+90° + 130°+ ∠p=360°
⇒ 310°+ ∠P=360°
⇒ ∠P=360°-310°
⇒ ∠P=50°

Class 8 Maths Chapter 3 Exercise 3.3 Solution in Video

for more answers vist to:
https://www.tiwariacademy.com/ncert-solutions/class-8/maths/chapter-3/