After constructing a voltage divider to reduce the voltage from my power supply (Output 10kV, 30mA) an oscilloscope probe was used in hopes of measuring the output voltage of the system. Due to the way this system functions a DMM could not be used due to the high pulses of voltage outputted by the power supply as the input voltage increases. That is why I thought it would be best to use an oscilloscope with a voltage divider to measure this voltage. In my case the voltage divider was configured where R1 = 64.1MΩ and R2 = 1.298MΩ (R1 was initially set at 23.00MΩ however my oscilloscope could not read the output voltage as high as was needed so the resistance of R1 was increased). After performing the calculations necessary to determine the amount the output voltage seen on the oscilloscope needs to be multiplied by, a multiplier of 52.15 is produced. I followed the math seen on this post (Measure high voltages with a multimeter) which resulted in this value however it seems to be too high. Did I simply calculate incorrectly or is the equation found there incorrect? (A high voltage probe is being used with an impedance of 40MΩ which has been taken into account when calculating the multiplier.)
Your setup won't be very good at high frequencies. I guessed at some of the scope probe and scope values, but with the circuit below, the bandwidth is only about 40 kHz. I haven't accounted for all the parasitics, it could be worse.
If you need higher bandwidth than this, you can buy 1000x high voltage scope probes.
Your probe has an input impedance of 40M\$\Omega\$ in parallel with 2.5pF, according to this Tektronix page. At, say, 100kHz the 2.5pF has a reactance of < 1M\$\Omega\$, so it acts as a low-pass filter.
To get this to read correctly with a high bandwidth you would need to parallel the 64M resistor with a small capacitance (rated for the high voltage involved). Getting the right value and trimming it (or some added capacitance across the probe input) would be non-trivial. High voltage scope probes are expensive.