Theo was asked to find the measure of x in the following polygon.

A polygon has angles 63 degrees, 63 degrees, x, and x.

Theo’s work is shown below.

Steps
Theo’s Work
Step 1
(n minus 2) 180 degrees = (4 minus 2) 180 degrees
Step 2
2 (180 degrees) = 360 degrees
Step 3
63 degrees + 63 degrees + x degrees = 360 degrees
x = 234 degrees

Where, if at all, did Theo first make a mistake finding the measure of x?
step 1
step 2
step 3
Theo did not make a mistake.