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If the scale of a chart is 10 cm to 40 NM, then the scale as representative fraction is…

  • A

    1 : 541 280

  • B

    1 : 700 000

  • C

    1 : 741 200

  • D

    1 : 750 350

The chart's scale illustrates the relationship between the depicted length on the chart and the actual distance on Earth's surface and is commonly expressed as a fraction, for example "1: 1 000 000": 

  • Chart Scale = Chart distance / Earth distance

1. Convert the Earth distance to cm:

  • 1 m = 100 cm
  • 1 NM = 1852 m
  • 40 NM x 1852 m x 100 cm = 7 408 000 cm

2. Simplify the ratio:

  • Initial ratio is 10 cm : 7 408 000 cm
  • Divide both numerator and denominator by 10:
    • 10 / 10 = 1
    • 7 408 000 / 10 = 740 800

Therefore, the representative fraction is 1: 740 800, closest option 1: 741 200.

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