The chart indicates the variation was 3°45'W in 1988, and the annual change is decreasing 6'. If you use the chart in 1991 how much variation should you apply?

Question

The chart indicates the variation was 3&deg;45'W in 1988, and the annual change is decreasing 6'. If you use the chart in 1991 how much variation should you apply?

Accepted Answer

Option A: 3&deg;27'W. Annual variation decreases 6' per year. From 1988 to 1991 is 3 years, yielding an 18' decrease. Subtracting 18' from 3Þg45'W gives 3Þg27'W, since westerly variation is decreasing.

The chart indicates the variation was 3&deg;45'W in 1988, and the annual change is decreasing 6'. If you use the chart in 1991 how much variation should you apply?

The chart indicates the variation was 3°45'W in 1988, and the annual change is decreasing 6'. If you use the chart in 1991 how much variation should you apply?