Question

a survey line cd intersects a building to over come the obstacle a perpendicular DE 87 m long is set out D from E two lines EF and EG are out at D from E two lines EF and EG are set out at angles of 50 and 65 respectively with ED find the length EF and EG such that points F and G fall on the prolongation of CD also find the obstructed distance DF
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Answer 1

Answer:

 

Examples – Obstacles in Chaining

Example 1:

A survey line CD intersects a building. To overcome the obstacle a perpendicular DE, 87 m long; is set out at D. From E, two lines EF and EG are set out at angles 50

o

and 65° respectively with ED. Find the lengths EF and EG such that points F and Gfall on the prolongation of CD. Also find the obstructed distance DF.

Solution:

From

Δ

DEF,



=



50





=

50



=

870

.

6428

= 135.345





=



50



DF =



×



50



= 87 ×1.1918 = 103.68



From

Δ

DEG,



=



65





=

65



=

870

.

4226

= 205.9



Explanation: