Р=(2+4)*2=16 см
Нашла с помощью периметра
1. Before you cross the road look both ways.
2. Don't cross parket between cars.
3. Don't ride against traffic.
4. Wear a bicycle helmet.
5. Stand on the pavement.
Х-одно число
4х - второе число
(х+4х)/2=8,5
5х/2=8,5
5х=17
х=17/5
х=3,4 - первое число
второе число 3,4*4=13,6