Ammonia and oxygen react to form nitrogen monoxide and water, like this:

4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)

Also, a chemist finds that at a certain temperature the equilibrium mixture of ammonia, oxygen, nitrogen monoxide, and water has the following composition:

Compound Pressure at equilibrium
NH3 36.2atm
O2 77.6atm
NO 87.8atm
H2O 9.77atm

Calculate the value of the equilibrium constant Kp for this reaction.