Step-by-step explanation:
so, the garden seems to be rectangular.
it has a length.
and width = length - 2
I assume the fence should go all around the rectangular garden.
that means it has to cover 2 lengths and 2 widths.
fence = 2×length + 2×(length - 2) =
= 2×length + 2×length - 4 = 4×length - 4 =
= 4×(length - 1)
length = 7.5 m
so, he will need
4×(7.5 - 1) = 4×6.5 = 26 meter of fencing.
