Civil Engineering - Surveying - Discussion

No ^ terms mean the answer is to be in *a* degree, by only looking at options.

Let's assume L*a=h like in h^2/2L.

This gives in terms of a^2.

= h^2/2*l
= (l sina)^2/2*l.

= l*a^2/2 [in radian converting to degree i.e. (pi/180)^2].
= 0.00015*l*a^2.
= 1.5/100*a^2.

in these questions of slope correction, to arrive at the answer form the given options; I found the unit to be the key. here answer could be in mm, cm or m. we just need to analyze units ourselves based on the answers provided.
Here,
1. slope correction is h^2/(2*L)
2. As the answer is in terms of 1.5, let the chain length be 30 m and not 20m. Otherwise, we can't arrive at 1.5.
3. The slope correction = α^2*L^2/(2L) = α^2 * L/2 = α^2 *15 m.
4. α^2 *15*10^-3 mm. = 1.5*α^2/100 mm.