I saw that in the article, too, but it didn't make sense to me. One has units of area and the other has units of length. How can they possibly be equal? That's like saying a 700 foot wall is the same size as a 700 square foot apartment.
That's what made it jump out to me too! But the key thing is that one number is in linear units and the other is in square units. So for any linear unit you choose (mm, in, km, furlongs, ...) an equilateral triangle with perimeter sqrt(432) units will have area sqrt(432) square units.
