A circle has a diameter of 20 cm.
The line AC is a diameter of the circle.
B is a point on the circumference of the circle with AB = 12 cm. The point D lies on the arc AC on the opposite side to point B.
What is the sine of ∠BDC?
<BDC=<BAC they are both subtended from arc BC so they are congruent
<ABC = 90degress (angle in a semicircle)
Cos(<BAC) = 12/20
and you can finish it.
+4 
+118654 
