# what is the length of an arc?the formula

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Since the problem does not specify detailed information, I'll consider the two formulas of the length of arc such that:

- writing the formula of length of arc of circle yields:`l= r*C`

r denotes the radius of circle; C denotes the angle subtended at the ccenter of circle by the endpoints of arc.

- writing the formula of length of graph of function f(x) over an interval [a,b] yields `L = int_a^b (sqrt(1 + (f'(x))^2)) dx`

f'(x) denotes first derivative of function f(x)

**Hence, you may use the following formulas to determine the length of arc, in terms of information provided by the problem such that:`l = r*C; L = int_a^b (sqrt(1 + (f'(x))^2)) dx.` **