Answer:
t = 5 kilometers
Explanation:
From the given figure,
Perimeter = 18 kilometers
Now, the formula for perimeter of a rectangle = 2(l + b)
Where,
'l' is the length of the rectangle
and
'b' is the breadth of the rectangle.
Since length is the longest side of a rectangle, therefore from the given figure
=> l = t kilometers
and
=> b = 4 kilometers
Substituting values in the formula,
18 = 2(t + 4)
=> 18/2 = t + 4
=> 9 = t + 4
=> 9 - 4 = t
=> t = 5 kilometers