Step-by-step explanation:
in an equilateral triangle all 3 sides have the same length.
so, when one side measures 5 3/8 cm, then all 3 sides have the same length.
this "5 by 3/8 cm" phrasing is strange. normally that would be used for an area giving 2 dimensions. but here it is clearly meant to describe one dimension, length.
so, I can only assume this means the side is 5 3/8 cm long.
the perimeter of the triangle is simply the sum of all ways needed to walk around the whole triangle : the sum of all 3 sides.
we could do this 2 ways (1. convert 5 3/8 into one big fraction and do the calculation, 2. stay with 5 3/8 and do the calculations there).
I think 1. it's easier to understand and to also use it for other similar problems.
so,
5 3/8 = (5×8 + 3)/8 = (40 + 3)/8 = 43/8
we have 3 sides of equal length
Perimeter = 3×43/8 = 129/8 = 16 1/8 cm
