In a series circuit, the total resistance is the sum of the individual resistances.
Given that there are three 30.0 Ohm resistors connected in series, the total resistance \( R_{\text{total}} \) can be calculated as follows:
\[ R_{\text{total}} = R_1 + R_2 + R_3 \]
Since all resistances are equal to 30.0 Ohm:
\[ R_{\text{total}} = 30 , \Omega + 30 , \Omega + 30 , \Omega = 90 , \Omega \]
Thus, the total resistance of the circuit is 90 Ω.