In triangle ABC,∠A=130∘,BC=10cm. The diameter of the circumcircle is [sin 50∘=0.76]
13.15 cm
Draw diameter BD and join CD
ABCD in a cyclic quadrilateral so ∠CDB=180∘−130∘=50∘
∠BCD=90∘ (Angle subtended by diameter on circumference)
In right-angle triangle BCD
sin 50∘=BCBD⇒=BCsin 50∘=100.76=13.15cm
Hence, diameter BD=13.15cm