1 4/20 = 24/20
24/20 - 3/20 = 24/20 - 3/20 = 21/20 - ширина
Р = 2 * ( 24/20 + 21/20) = 2 * 45/20 = 45/10 = 4 целых 5/10 = 4 целых 1/2
1 4/20 = 24/20
24/20 - 3/20 = 24/20 - 3/20 = 21/20 - ширина
Р = 2 * ( 24/20 + 21/20) = 2 * 45/20 = 45/10 = 4 целых 5/10 = 4 целых 1/2