1.
it says 1.8 for human and for humans shadow is 4.5 so what we should do is;
4.5-1.6= 2.7
so it says 8 meters for trees shadow so;
8.0-2.7= 5.3
sorry i dont have time to do all but for second question i think you should do;
draw lines like it did for 3 and 4, and for the last one (the answer) is should be 7
