Explain how this figure is a trapezium. Which is its two sides are parallel?

Here, ∠m+ ∠L= 100°+80°=180°
[Sum of interior opposite angles is ] 180°
∴ NM and KL are parallel.
Hence, KLMN is a trapezium.

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/