Subject: General Aptitude · Chapter: Area · Exam: 2006 · Marks: · Difficulty:
A one-rupee coin is placed on a plain paper. How many coins of the same size can be placed round it so that each one touches the centre and adjacent coins?
(a)3
(b)4
(c)6
(d)7
Answer
Answer (as printed): C
Explanation
When 3 congruent circles touch each other externally, the triangle formed with their centres is an equilateral triangle. Hence, when a circle is surrounded by identical circles, centres of two consecutive circles make an angle of 60° with the central circle. Thus, six identical circles can surround a circle of equal radius.
Explanation as extracted from the printed page; notation may be imperfect.