Question

Find the value of $\angle$COB.

• A. ${130}^{\circ }$
• B. ${140}^{\circ }$
• C. ${150}^{\circ }$
• D. ${160}^{\circ }$

Answer 1

The correct option is C

${150}^{\circ }$

Two angles are called supplementary angles, when they add up to ${180}^{\circ }$.

$\angle$COA + $\angle$COB = ${180}^{\circ }$ (linear pair)

${30}^{\circ }$ + $\angle$COB = ${180}^{\circ }$

$\angle$COB = ${150}^{\circ }$