Nolan used the following procedure to find an estimate for StartRoot 18 EndRoot. Step 1: Since 4 squared = 16 and 5 squared = 25 and 16 < 18 < 25, StartRoot 18 EndRoot is between 4 and 5.
Step 2: Since 18 is closer to 16, square the tenths closer to 4.
4.1 squared = 16.81
4.2 squared = 17.64
4.3 squared = 18.49
4.4 squared = 19.36
Step 3: Since 18.49 rounds to 18, 4.3 is the best approximation for StartRoot 18 EndRoot.

In which step, if any, did Nolan make an error?
In step 1, StartRoot 18 EndRoot is between 4 and 5 becauseStartRoot 18 EndRoot almost-equals 20 and 4 times 5 = 20.
In step 2, he made a calculation error when squaring.
In step 3, he should have determined which square is closest to 18.
Nolan did not make an error.