<p>This question has the answer is B, Do I have to recognise any pattern of this rhombus? Thanks a lot</p>
<p>The figure is not only a rhombus--it is also a pair of equilateral triangles. Try to approach the problem from this angle: the line segment AC is actually just a pair of triangle altitudes (one from triangle ABD and one from triangle BCD). If you're still having trouble with it, let me know and I can give you my solutions to the problem.</p>
<p>Since it is a equilateral, its angle suppose to be 60. The segment is square root of 3, but that is where I am, how do I get the ratio really?</p>
<p>Thanks</p>
<p>The segment is actually half of the square root of 3, if you're setting all of the line segments equal to a length of 1. Then, the whole length of AC (which, remember, is made of two altitudes) is two times half of the square root of 3, or just the square root of 3. So, BD = 1 and AC = square root of 3. Does that make sense?</p>
<p>OK, I get you, this makes perfect sense, thanks a lot.</p>