9th Class
Mathematics
Geometry
Question Bank
Geometry
question_answer
In the diagram, 0 is the centre of the circle. The angles CBD is equal to
A)\[25{}^\circ \]
B) \[50{}^\circ \]
C)\[40{}^\circ \]
D)\[130{}^\circ \]
Correct Answer:
A
Solution :
Angle subtended by Arc ABC at the centre \[\therefore \]Angle subtended by Arc ABC at any point on the circumference \[={{25}^{o}}\] \[\therefore \] \[\angle ABC={{180}^{o}}-{{25}^{o}}={{155}^{o}}\] [Since opposite angles of a cyclic quadrilateral are supplementary] \[\therefore \] \[\angle CBD={{180}^{o}}-{{155}^{o}}={{25}^{o}}\]