could someone explain how you can use thales theorem to find sinA as the question hints?(click on link below) I have solved the larger of the two right triangle for DB. then found C and and B of the same triangle with arctan. i also know by pythagorean theorem that the smaller triangle is a similar right triangle to the larger and D is 90deg. so i use the sine law to find the lenght of AC and AD.

BUT! the book has not even gone into law of sine and cosine yet. i answered a, b and c. but still have no idea how he wants me to use thales theorem to find siaA? or how to find AC AD without law of sine.