Angles in the same segment of a circle area are

An equilateral triangle of side 9 cm is inscribed in a circle. The radius of the circle is

The angle in a semicircle measures

In the given figure, ΔABC and ΔDBC are inscribed in a circle such that ∠BAC = 60° and ∠DBC = 50°. Then, ∠BCD = ?

In the given figure, BOC is a diameter of a circle with centre O. If ∠BCA = 30°, then ∠CDA = ?