Answer:
Make Width = 'x'
Length = 4 + 2x
Perimeter = 2 x Width + 2 x Length
86 = 2(x) + 2(4 + 2x)
86 = 2x + 8 + 4x
Collect like terms:
2x + 4x = 86 - 8
6x = 78
x = 13
Width = 13 cm
Length = 30 cm
Step-by-step explanation:
The unknown dimension is 35
The perimeter of a rectangle is l+l+w+w or 2l+2w (l=length, w=width)
then we subtract 14 from 84
Let's check our answer
<u>Hope this helps :-)</u>
Answer: -144.1226