The given sequence is \( 3, 6, 9, \ldots \). This is an arithmetic sequence where the first term (\( a_1 \)) is 3 and the common difference (\( d \)) is 3.
The formula for the \( n \)-th term of an arithmetic sequence is given by:
\[ a_n = a_1 + (n - 1) \cdot d \]
To find the 70th term (\( a_{70} \)), we can substitute \( n = 70 \), \( a_1 = 3 \), and \( d = 3 \) into the formula:
\[ a_{70} = 3 + (70 - 1) \cdot 3 \] \[ a_{70} = 3 + 69 \cdot 3 \] \[ a_{70} = 3 + 207 \] \[ a_{70} = 210 \]
Thus, the 70th term of the sequence is \( \boxed{210} \).
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