Answer:
189.84%
Step-by-step explanation:
We make the say that 64 is 100% because it is our output value.
Next up we represent the value we seek with $x$.
Therefore it follows us up with $100\%=64$.
That also gives us the same vein, $x\%=121.5$.
Which then gives you and I a pair of simple equations: 100\%=64(1) and x\%=121.5
Then by dividing the equation 1 by equation 2 and taking note of the faction of both equations. They then have the same unit (%); we got.
Then you just keep doing what you learned and eventually you will get $121.5$ is $189.84375\%$ of $64$.
Therefore, $121.5$ is $189.84375\%$ of $64$.