Answer:
81 strikes
Explanation:
First, lets figure out how many strikes for each inning. If you need 3 strikes for 1 out, and you need 3 outs per inning you would multiply 3 strikes by 3 outs to get 9 strikes for inning 1.
So, you now know that you need 9 strikes per inning, so lets take those 9 strikes per inning and multiply that by 9 innings total. 9x9=81.
You now know that a pitcher would need to throw 81 strikes to throw a perfect game.