Answer:
That is the third one :
456.222
because it has the most numbers 4,5,6 and point . 2,2,2
an equilateral triangle has a square root height if 3 so I'm guessing if you multiply square root of 3 times 8
first make two triangles using M , so there iwll be 90-45-45, and 30-60-90 then use the side rules of those special triangles
2 significant digits should be represented in the product