Quadrilateral A B C D is inscribed in a circle with \angle B A C=70^{\circ}, \angle A D B=40^{\circ}, A D=4, and B C=6. What is A C ?
Answer Choices
A. 3+\sqrt{5}
B. 6
C. \dfrac{9}{2} \sqrt{2}
D. 8-\sqrt{2}
E. 7
Quadrilateral A B C D is inscribed in a circle with \angle B A C=70^{\circ}, \angle A D B=40^{\circ}, A D=4, and B C=6. What is A C ?
Answer Choices
A. 3+\sqrt{5}
B. 6
C. \dfrac{9}{2} \sqrt{2}
D. 8-\sqrt{2}
E. 7