ABCD is a quadrilateral inscribed in a circle with centre O. If ∠COD = 120 degrees and ∠BAC = 30 degrees, then the value of ∠BCD (in degrees) is
Explanation:
Angle subtended by an arc on circle is half of the angle it makes at the center. ∴ Considering arc CD, it makes an angle of 120° at the center hence ∠CAD = 60°.
⇒ ∠BAD = 90°
Now, in a cyclic quadrilateral, sum of opposite angle = 90°.
⇒ ∠BAD + ∠BCD = 90° ∴ ∠BCD = 90°
Hence, 90.
» Your doubt will be displayed only after approval.
Help us build a Free and Comprehensive Preparation portal for various competitive exams by providing us your valuable feedback about Apti4All and how it can be improved.