Question

Which of these angles cannot be constructed using only one type of set square?

• A. $150°$
• B. $135°$
• C. $120°$
• D. $105°$

Answer 1

The correct option is D $105°$

150 degree can be constructed aligning 90 and 60 degree corners as needed.
135 degree is constructed aligning 90 and 45 degree corners as needed.
120 degree is constructed aligning 90 and 30 degree corners as needed.

105 degree is constructed aligning 60 and 45 degree corners as needed. However, these are corners of different set square systems.