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In the circuit above, $R_1 = 2R_3$ and $R_3 = 2R_2$. If the source voltage is $V_1$, find the power dissipated in $R_1$.

$$\frac{(V_1)^2}{7R_2}$$

$$\frac{(V_1)^2}{14R_2}$$

$$\frac{(3V_1)^2}{7R_2}$$

$$\frac{(V_1)^2}{49R_2}$$

$$\frac{(3V_1)^2}{49R_2}$$