Questions

The logic in the challenge is

 81x6 = 9x6 = 54

144x7=84

Similarly, 64x8 = 8x8 = 64.

The atmospheric pressure at the surface of the Earth is due to gravitational pull of the earth and is about 14.7 psi.

That means that the weight of a column of air which has a cross section of 1 square inch and which stretches from the surface of the Earth to space is 14.7 pounds. 

The azimuth originates at true North i.e, the azimuth originates from the north point. It is a measure of how far an object forms the observer's north point.

Azimuth is a technical mapping term which is used to describe the direction of an angle between north and south on a compass circle through which the circle line passes. It is the most common military method to express direction. When using an azimuth, the point from which the azimuth originates is the center of an imaginary circle.