Hi, for part (ii), try to visualize an imaginary circle with radius AC and centre at A, then AD is also the radius of this circle. From here, you can then apply the area of sector formula to find the area of sector CAD. Over here, I used sine rule to calculate the length AC (since the triangle COA is not right therefore I cannot use basic trigonometric rules or Pythagoras Theorem to find AC), you can use cosine rule as well. Leave a comment if you still need help / clarifications!