Question

If one angle of cyclic quadrilateral is ${70}^o$, then the angle opposite to it is:

• A. ${20}^o$
• B. ${110}^o$
• C. ${140}^o$
• D. ${160}^o$

Answer 1

Answer: (B)

${110}^o$

In the cyclic quadrilateral,

angles $A+C={180}^{\circ }$, and angles $B+D={180}^{\circ }$......(opposite angles of acyclic quadrilaterals are supplimentry).

So, if one of the angle is ${70}^{\circ }$.

Then, angle opposite to it is $={180}^{\circ }-{70}^{\circ }={110}^o$.

Hence, option $B$ is correct.