That common ancestor of chimps and man was an ape. Apes diverged from monkeys about 30 million years ago, IIRC. Your ancestor was on the "ape" branch.
You have said that DNA evidence eliminates hippos as any sort of relative of whales.
The source is in post#1651 (or should I repost it again since perhaps you will deny that I ever posted if I just give you a post#). However, it is very dishonest of you to ask for this proof since you know quite well that science has been saying for decades that man and apes have a common ancestor not that man descended from monkeys as the charlatan Darwin said.