For an Ac signal with peak voltage Vp equal to 60V, the same power would be delivered to a load with a dc voltage of

30√2 ≈ 42.426 volts

Explanation:

The RMS value of the signal is the DC equivalent. For a sine wave, the mean of the square is half the square of the peak value. Then the Root-Mean-Square is ...

RMS = √ ((Vp) ^2/2) = Vp/√2

For Vp = 60 volts, the equivalent DC voltage is ...

V = (60 volts) / √2 = 30√2 volts ≈ 42.426 volts