Sum of interior angles of a △ = 180°
∴ ∠T + ∠V + ∠U = 180°
⇒ 37° + 63° + X° = 180°
⇒ X° + 100 = 180°
⇒ X° = 180° - 100°
⇒ X° = 80° (D).
It's a translation.
A reflection across a line is like flipping that object like a pancake over the line. It gets turned upside-down.
When you flip the pancake again, now across a parallel line, it gets turned right-side up again, just in a new location.
20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40
