Find a and d for the function f(x) = a cos(x) + d

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The appalachian trail is a hiking trail that passes through the appalachian mountains. three members of a teen hiking group hiked a section of the trail. the hikers stopped at a rest area and equally shared 3 4 gallon of water. how much water did each person get?

What is the measure of angle afe? 79 81 91 99