the black part is a formula that is very important for solving this question. Use it to solve part a i and ii. After you do so, part b i will use Pythagoras Theorem (A²+B²=C²). b ii will use the sin a / A = sin b / B again. b iii) is not shown there but remember that shortest distance means that the line that touches AB (CD) will always be perpendicular (90 degrees). Use the same method as part b ii) and you can find b iii). The answer for b iii) is 26.2 (1 dp since it's a degree). I think the problem with this sort of question is that it's hard to visualise the triangles.