Question

Help, I don't understand this whatsoever ;o

Answer 1

Well they tell you that the rhombus is labelled BCDE thus you know that the segment BC is a side. Now you find its length via the distance formula:
\[\sqrt{(\Delta y)^{2}+(\Delta x)^{2}}\]

So let's take BC: the change in x is 0-(-1) = 1. The change in y is -2-5 = -7. The square of these is 1 and 49, respectively. Their sum is 50 but the distance is the square root of that, thus
\[\sqrt{50}\]
Then you need to verify for CD DE and EB

Answer 2

is it the last one then? @khoala4pham

Answer 3

Yah. I just did the math in my head. It's all the same length.

Answer 4

Although I would recommend you do the work to receive credit.