To measure distance on a Mercator chart...

Question 1 of 2707066636ee928f7522a1c519bcd

To measure distance on a Mercator chart between the parallels of LAT 34°30'N and LAT 31°30'N, which 30- mile scale should be used?

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Question 1 of 27070

To measure distance on a Mercator chart between the parallels of LAT 34°30'N and LAT 31°30'N, which 30- mile scale should be used?

🔍 Key Concepts

• On a Mercator chart, the distance scale (minutes of latitude) is only accurate at the latitude where you take it from • For a given distance between two latitudes, you normally use the mid-latitude (average of the two) to pick the correct scale • Understand how 1 minute of latitude ≈ 1 nautical mile and how that relates to a short 30-mile segment on the chart

💭 Think About

• First, find the mid-latitude between 34°30'N and 31°30'N; which of the answer choices includes a 30' band that is closest to this mid-latitude? • Think about whether you want a scale taken from higher, lower, or about the same latitude as the distance you’re measuring—how does that affect accuracy on a Mercator chart? • Look at each 30′ band in the options: which one’s center latitude best matches the center of the latitude band you’re measuring between?

✅ Before You Answer

• Compute and write down the average latitude between 34°30'N and 31°30'N • For each answer choice, find the central latitude of the 30′ band and compare it to your computed average • Make sure the chosen 30-mile scale comes from the latitude band whose center latitude is closest to the mid-latitude you found