Solution: 17÷ad⊥bc∴△Abd and △ADC are Rt△, and ÷∠Abd = 30 ab = 8∴ad = 4 (the opposite side of 30 in a right triangle is equal to half of the hypotenuse) bd =

18 BC = sin∠BAC * ab = 3/5 * 15 = 9 ac^2=ab^2-bc^2= 15^2-9^2= 144 AC = 12 DC = BC-BD = 9-4 = 5

tan∠ADC=AC/DC= 12/5