1. Find the Correct Conversion:

* The correct conversion of 20ºC to Fahrenheit is:

* (20 * 9/5) + 32 = 68ºF

2. Calculate the Error:

* Error = |Incorrect Value - Correct Value|

* Error = |64ºF - 68ºF| = 4ºF

3. Calculate the Percent Error:

* Percent Error = (Error / Correct Value) * 100%

* Percent Error = (4ºF / 68ºF) * 100%

* Percent Error ≈ 5.88%

Therefore, the approximate percent error in the student's conversion is about 5.88%.