FUNDAMENTAL SURVEYING Angles, Bearings & Azimuths 1 — Questions and Answers
Question 1: What is a 'deflection angle' in surveying?
- The angle between magnetic north and a survey line
- The angle measured right or left from the extension of the preceding course (Correct answer)
- The interior angle of a closed traverse
- The vertical angle measured from the horizon
Correct answer: The angle measured right or left from the extension of the preceding course
A deflection angle is measured from the prolongation of the back course to the forward course, designated R (right) or L (left).
Question 2: What does magnetic declination represent?
- The dip of the magnetic needle below the horizon
- The horizontal angle between magnetic north and true geographic north (Correct answer)
- The annual change in magnetic field strength
- The difference in elevation between two magnetic stations
Correct answer: The horizontal angle between magnetic north and true geographic north
Magnetic declination is the horizontal angular difference between where a compass needle points (magnetic north) and true geographic north.
Question 3: An azimuth of 090 degrees corresponds to which cardinal direction?
- North
- East (Correct answer)
- South
- West
Correct answer: East
Azimuths are measured clockwise from north: 0=N, 90=E, 180=S, 270=W.
Question 4: To compute the back azimuth of a line with a forward azimuth of 60 degrees, you would:
- Subtract 60 from 360
- Add 180 to 60 (Correct answer)
- Subtract 60 from 180
- Multiply 60 by 2
Correct answer: Add 180 to 60
Back azimuth = forward azimuth plus or minus 180; for 60 degrees, back azimuth = 60 + 180 = 240 degrees.
Question 5: A direction of S 72 degrees 15 minutes 30 seconds E is an example of a:
- Azimuth
- Bearing (Correct answer)
- Deflection angle
- Interior angle
Correct answer: Bearing
Bearings are expressed as angles from north or south toward east or west, with a quadrant designation like S 72 15 30 E.
Question 6: The sum of interior angles of a closed polygon traverse with 5 sides should equal:
- 360 degrees
- 540 degrees (Correct answer)
- 720 degrees
- 900 degrees
Correct answer: 540 degrees
Sum of interior angles = (n minus 2) times 180 = (5 minus 2) times 180 = 540 degrees.
FUNDAMENTAL SURVEYING Angles, Bearings & Azimuths 1
What is a 'deflection angle' in surveying?