Low water is 1.0 m at 0600 and high water is 5.8 m at 1200. By the rule of twelfths, what is the height of tide at 0800?
A graph of a rising tide: low water of 1.0 m at 0600, climbing in a smooth S-shaped curve to high water of 5.8 m at 1200, with each hour marked along the bottom. A gold marker with a question mark sits on the curve at 0800.
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2.2 m. The tide rises 1, 2, 3, 3, 2 and 1 twelfths of its range in the six hours. The range is 4.8 m, so after two hours it has risen 3 twelfths, which is 1.2 m. Add that to the low water height of 1.0 m to get 2.2 m.
