1. Supplementary angles : Two angles are supplementary if their sum is 180°.
For angle 1 and ∠COF to be supplementary,
∠1 + ∠COF =180°
must be satisfied.
We see in the figure that angle 1 and COF form a straight line.
The angle of a straight line is 180°.
∴ 1 is a supplement of ∠COF.
Answer : YES
2. Given : ∠COF =150° ;
AD is perpendicular to BF.
Here, ∠BOC + ∠COF = 180° , since they form a straight line.
∠BOC = 180° - ∠COF = 180° - 150° =30°
∴ ∠BOC = 30°
Answer : D. 30°
