What the methods and tricks that one can use when dealing with Euclidean geometry.​

Asap will give brainliest and a lot of points

Money off coupons have been circulated to 300 households. only 2/5 of these were redeemed (used) in the local supermarket to get a free shampoo. what fraction of coupons were unused? (ps: write how you got the answer)

How can you find the mean absolute deviation (mad) for this set of data?