In airport planning, two runways have end coordinates (5000, 5000)–(8000, 7000) and (4600, 5100)–(7000, 5300). Determine the Airport Reference Point (A.R.P.) by averaging the geometric midpoints of all runways.

Difficulty: Medium

Correct Answer: (6150, 5600)

Explanation:


Introduction:
In airport engineering, the Airport Reference Point (A.R.P.) is a designated geographical position that represents the approximate center of the aerodrome. For a system of runways, a common approach is to compute the A.R.P. as the average of the midpoints of the individual runways, giving a balanced reference for charts, surveys, and navigation data.


Given Data / Assumptions:

  • Runway 1 endpoints: (5000, 5000) and (8000, 7000).
  • Runway 2 endpoints: (4600, 5100) and (7000, 5300).
  • A.R.P. taken as the mean of runway midpoints.


Concept / Approach:

The midpoint of a line with endpoints (x1, y1) and (x2, y2) is ((x1 + x2) / 2, (y1 + y2) / 2). The A.R.P. is then computed as the average of all runway midpoints when multiple runways exist.


Step-by-Step Solution:

Midpoint R1 = ((5000 + 8000) / 2, (5000 + 7000) / 2) = (6500, 6000)Midpoint R2 = ((4600 + 7000) / 2, (5100 + 5300) / 2) = (5800, 5200)A.R.P. x = (6500 + 5800) / 2 = 6150A.R.P. y = (6000 + 5200) / 2 = 5600Therefore, A.R.P. = (6150, 5600)


Verification / Alternative check:

The two midpoints lie reasonably close; their average must fall between them. (6150, 5600) lies between (6500, 6000) and (5800, 5200), confirming plausibility.


Why Other Options Are Wrong:

  • (6500, 6000): This is only the midpoint of Runway 1, not the average of both runways.
  • (5800, 5200): This is only the midpoint of Runway 2.
  • (8000, 7000): This is an endpoint, not a representative center.
  • (6200, 5550): A nearby estimate but not the exact computed average.


Common Pitfalls:

  • Choosing the midpoint of the longest runway instead of averaging all runways.
  • Accidentally averaging endpoints directly rather than averaging midpoints.


Final Answer:

(6150, 5600)

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