Can u please help me on this problem? :(
No links plz..

triangle ABD is a equilateral triangle.

so each angle is 60°

<ADB=60°

<BAD=60°

again

we have

CD is perpendicular to AD[tangent on the arc is perpendicular to the radius]

:. ADC=90°

°

again

In triangle ADC

<A+<B+<C=180°[sum of a interior angle of a traingle is 180°]

60°+90°+x=180°

x=180°-150°

x=30°

is a right answer.