the same as 6789+436. 85x85 is the same as 8 to the power of 2 The answer is 7225
The largest you'll probably be able to find outside of custom work is 85x85. It will typically offer about 90lbs of resistance, and should be enough for even the largest person.
The two numbers that multiply together to equal 7225 are 85 and 85. This is because 85 multiplied by 85 equals 7225. In mathematical terms, 85 * 85 = 7225.