Also again for MC Q8 shouldn't the answer be 144? Because 1 x 1 x 4! x 3!, not your solution of 2 x 4! x 3!.
This is because it is a circular table so you have to place one individual down and set them there hence the 1 x 1 instead of 2?
However, Permutations and Combinations aren't my best...
Is the answer cosθ ?
If so, just sub tan(θ/2) for t
and you get 1 + (tan(θ/2))^2 at bottom which can be equated using the trig identity to (sec(θ/2))^2
and take it from there
Why would it not give you 3/3?
If all your working was there and it was correct, then they would give you 3/3. There are multiple ways of doing basically all questions. You'll be fine as long as you wrote everything needed.
I also used similar triangles btw, but I just proved triangle ACD is...
Unless of course, you didn't try at all/had other issues during HSC year. Try self teaching for a bit YouTubers such as Eddie Woo cover 2U, 3U content really well. Then make the decision if you want to do a bridging course or not (you will probably need it do engineering right?). If you want it...