Answer:
16 cm
Step-by-step explanation:
Let the width be x
The length will be 3 x since the length is three times the width
Perimeter=2(l+w) where l is length and w is width
By substituting 128 cm for perimeter, x for w and 3 x for l then
128=2(3x+x)
128=8x
Therefore, the width is 16 cm, the width is 16*3=48 cm
Equation
L = a + (n - 1)*d
Givens
L = 55
a = 13
n =8
Solution
55 = 13 + (8 - 1)*d Combine
55 = 13 + 7d Subtract 13 from both sides
55 - 13 = 7d
42 = 7d Divide by 7
d = 6
5000o