GATE 2020 CE (CE2) – Question 65

Geomatics Engineering · Distance and angle measurement, levelling, traversing, triangulation, total station · 2 marks · Numerical answer

A theodolite at A has instrument-axis RL 212.250 m. Elevation angle to the top of a vertical 4 m staff at B is 7°. Horizontal AB is 400 m. Neglect curvature and refraction. Find B reduced level (m), to three decimals.

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Correct answer: 257.2 to 257.6

Explanation

Staff-top RL is $212.250+400\tan7^\circ=261.363824$ m. Subtract 4 m staff height to obtain **257.364 m**.