In the diagram above, the value of angles b + c is
Attached Figure / Diagram
A
a°
B
90°
C
180°
D
d°
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
∠BFC = 180° - a° (adjacent angles on a straight line)
∴ a° + b° + c° + ∠BFC = 360° (quadrilateral) a° + b° + c° + (180° - a°) = 360°
b° + c° = 360° - (180° - a°) - a°
b° + c° = 360° - 180° + a° - a°
b° + c° = 180°
Source: WAEC / JAMB / NECO Classroom Archive (Record #75909)