Answer is: the value of Kp at this temperature is 0.657.
Chemical reaction 1: 2NO₂ ⇄ N₂O₄.
Chemical reaction 2: N₂O₄ ⇄2NO₂.
Kp₁ = [N₂O₄] / [NO₂]²; equilibrium constant for chemical reaction 1.
Kp₂ = [NO₂]² / [N₂O₄]. equilibrium constant chemical reaction2.
Kp₁ = 1.52.
Kp₂ = 1 / Kp₁.
Kp₂ = 1 / 1.52.
Kp₂ = 0.657.