🔍 Key Concepts

• magnetic variation vs magnetic deviation • how charts show areas where the difference between true north and magnetic north is the same • special name for the line where variation is exactly zero

💭 Think About

• Ask yourself: what quantity must be the SAME at every point along an isogonic line? • Which chart feature tells you how many degrees you must add or subtract when converting between true and magnetic directions? • Look at the choices and separate the one that talks about 00 variation from the one that talks about any equal amount of variation.

✅ Before You Answer

• Confirm the definition of variation (difference between true north and magnetic north at a location) • Identify which choice refers to only zero variation and which could mean any constant value of variation • Verify that magnetic dip and magnetic latitude are different physical concepts not normally shown as lines on a standard nautical chart.