Let ABC be an equilateral triangle with orthocenter at the origin and the side BC on the line . If the co-ordinates of the vertex A are , then the greatest integer less than or equal to is
- A
2
- B
3
- C
5
- D
4

For an equilateral triangle, the orthocentre coincides with the centroid. Let be the foot of perpendicular from (origin) to line .
.
In an equilateral triangle, the centroid divides the median in the ratio , so and the full median .
The line is perpendicular to and passes through . Slope of is , so slope of is . This forces . ...(1)
Distance from to line equals :
.
Using : or .
and must lie on the same side of line (the orthocentre side). Testing both: gives a sign opposite to ; reject. So , .
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. Option (4).
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