Пусть KM = x, тогда MN = x - 10.
Так как периметр P = 26, то можем записать уравнение: MK + KN + MN = 26
Учитывая, что MK = KN, получаем: MK = KN = (26 - (x - 10))/2
\[ (26 - (x - 10))/2 + (26 - (x - 10))/2 + (x - 10) = 26 \]
\[ 26 - x + 10 + x - 10 = 26 \]
\[ 2x + x - 10 = 26 \]
\[ 3x = 36 \]
\[ x = 12 \]
\[ MN = 12 - 10 = 2 \]
\[ MK = KN = (26 - 2) / 2 = 12 \]
Ответ: MK = 12, KN = 12, MN = 2
P = RS + ST + RT
RS = ST
P = 2.5, RT = 1.3
\[ RS + ST = P - RT \]
\[ RS + ST = 2.5 - 1.3 \]
\[ RS + ST = 1.2 \]
\[ RS = ST = 1.2 / 2 = 0.6 \]
Ответ: RS = 0.6, ST = 0.6