The air pressure in a circular duct is measured with a manometer whose open arm is inclined at 45° to the horizontal. The manometer liquid has a density of 0.81 kg/L, and the vertical distance between the liquid levels in the two arms is 12 cm. Determine (a) the gauge pressure of the air in the duct (in kPa) and (b) the length L of liquid in the inclined arm above the liquid level in the vertical arm (in cm).