Question 801333
width (w) = L - 10
length (L) = L
p = 112

p = 2L + 2w
2L + 2(L - 10) = 112
2L + 2L - 20 = 112
4L - 20 + 20 = 112 + 20
4L = 132
4L/4 = 132/4
L = 33

check:
2(33) + 2(33 - 10) = 112
66 + 2(23) = 112
66 + 46 = 112
112 = 112