Source: https://s02cb53e98f0467e4.jimcontent.com/download/version/1437085798/module/10344365912/name/Chap%208%20-%20Exercices%206e%20-%20Axes%20de%20sym%C3%A9trie%20de%20panneaux%20de%20signalisation%20-%20CORRIGE.pdf