If the horizontal distance between a staff point and the point of observation is $d$, the error due to the curvature of earth is proportional to

If the quadrantal bearing of a line is N30,,aW, then the whole circle bearing of the line is

In levelling between two points A and B on the opposite banks of a river, the readings are taken by setting the instrument both at $A$ and $B$, as shown in the table. If the $R L$ of $A$ is 150.000 m , the $R L$ of $B$ (in m ) is __________ (rounded off to 3 decimal places).

Level position	Staff readings
	A	B
A	1.800	1.350
B	1.450	0.950

The results of a consolidated drained triaxial test on a normally consolidated clay are shown in the figure. The angle of internal friction is