An older toilet uses 27 l per flush, whereas a replacement toilet uses only 6 l per flush. if you flush the toilet four times per day, how many liters of water would you save in 1 year if you replaced your older toilet?

18

step-by-step explanation:

draw the shape and you will see that f and k are actually at adjacent vertices (points of the hexagon that are neighboring).   so find the distance between (1,2) and (4,2).   that is easy since (1,2) and (4,2) is just a vertical distance to count, which is 3.   it is a regular polygon which means all sides are congruent.   you have 6 sides (hexa) so multiply 6 by 3 to receive 18.