From https://vcvrack.com/manual/VoltageStandards#pitch-and-frequencies, f = 2 Hz \cdot 2^V for LFOs with their frequency knob at its default position. Solve for V to get V = log_2(f/2Hz). Use @dronehands’ result for f.
However, you can set the Hz directly on most LFOs, so knowing the voltage is unnecessary, unless you want to control the LFO with another module.