х - одна сторона

у - другая сторона

2х + 2у - периметр

[tex]\displaystyle\bf\\\left \{ {{2x + 2y - x = 57} \atop {2x + 2y - y = 66 }} \right. \\ \displaystyle\bf\\\left \{ {{x + 2y = 57 \: \: | \times ( - 2)} \atop {2x + y = 66 }} \right. \\ \displaystyle\bf\\ + \left \{ {{ - 2x - 4y = - 114} \atop {2x + y = 66 }} \right. \\ \\ y - 4y = 66 - 114 \\ - 3y = - 48 \\ y = - 48 \div ( - 3) \\ y = 16 \\ \\ x + 2 \times 16 = 57 \\ x + 32 = 57 \\ x = 57 - 32 \\ x = 25[/tex]

Ответ: 16 см и 25 см