Which of the following angles cannot be constructed using a protractor, a compass, and a sharpened pencil?
A
135°
B
90°
C
145°
D
60°
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
In classical constructions with compass and straightedge, 60° (equilateral), 90° (square), and 135° (90° + 45°) are constructible. 145° is not constructible in general (not a multiple resulting from bisections of constructible angles).
Source: WAEC / JAMB / NECO Classroom Archive (Record #74098)