Perimeter calculation

Question

This was a quiz question. What is the perimeter of the figure shown (no figure was shown) if all sides are equal? The answer choices were: 2mm, 4mm, 10mm

and 20mm. Their answer was 20mm, but no explanation is given. Is this an historic question that one would learn in a class?

Answer 1

One could consider the geometric shapes with equal sides such as a square, where the Perimeter is 4s

If P = 20

s = 20/4

s = 5

An equilateral triangle with 3 equal sides would have a perimeter of 3s

s = 20/3

s = 6.6667

It does sound like the figure would have definitely been helpful unless the objective of the question was to consider the sides of equilateral figures instead.