L=5W
P=2(L+W), using L found above in this equation gives us:
P=2(5W+W)
P=2(6W)
P=12W
W=P/12, we are told that P=70
W=70/12
W=5 5/6, and since L=5W
L=25+25/6
L=29 1/6
So the length is 29 1/6 cm and the width is 5 5/6 cm. If you wish to round to nearest tenths, length is 29.2 cm and width is 5.83 cm.
