Ezekiel Chapter 40 Vs. 25

 The South Gate

And there were windows in it and in the arches thereof round about, like those windows: the length was fifty cubits, and the breadth five and twenty cubits. Eze 40:25

the length was... Fifty long cubits would be 87 feet 6 inches.

This was the inside of the bigger area, which was 150 feet square. This area is 87 feet 6 inches square by 37 1/2 feet. The 150 feet square is speaking of the inner court. This other measurement is like an inner court within the inner court.

To the south gate (Eze. 40:24-27). The design and dimensions of both gates were identical to those of the gate facing east.