8. When measuring small pressure differences with a manometer, often one arm of the manometer is inclined to improve the accuracy of the reading. The air pressure in a circular duct is to be measure during a manometer whose open arm is inclined 45 degrees from the horizontal, as shown in Fig. 2.The density of the liquid in the manometer is 0.81 kg/L and the vertical distance between the fluid levels in the two arms of the manometer is 12 cm. Determine the gage pressure of air in the duct and length of the fluid column in the inclined arm above the fluid level in the vertical arm.