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Khan Academy
Khan Academy: Calculus: 2011 Calculus Bc Free Response #3A
Video shows how to use integrals to write a formula for the perimeter of an area bounded on one side by a function. Includes showing how to derive the arc length formula. [5:41]
Khan Academy
Khan Academy: Calculus: 2011 Calculus Bc Free Response #1D
Video shows how to derive the arc length formula and how to use it to determine the total distance a particle traveled during a given time interval. [8:34]