Math CentralQuandaries & Queries


Question from black:

A highway that has a 6% grade rises 6 ft vertically for every 100 ft horizontally. Which trigonometric ratio is being used in reporting the 6% grade? Explain why

Hi there.

You have three choices: sine, cosine or tangent.

Where is the "right angle" in your situation, do you think? Is either the 6 ft side or the 100 ft side the hypotenuse of the triangle? If not, then sine and cosine are ruled out, because they both use the length of the hypotenuse.

Hope this helps,
Stephen La Rocque.

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