Question

Which of the following is not true regarding concentric and eccentric circles?

(a) Concentric circles have a common centre point

(b) Eccentric circles have no common centre point

(c) Concentric circles have no common centre point

(d) Two or more circles with a common centre point are called concentric

I had been asked this question in final exam.

Enquiry is from Curves Used in Engineering Practice topic in section Lettering Practice, Scales & Curves of Civil Engineering Drawing

Answer 1

The correct option is (d) Two or more circles with a common centre point are called concentric

Easiest explanation: When a circle is fully contained within another circle, they can be either eccentric or concentric. If they share the same centre, they are called concentric (please refer figure a) or else, they are said to be eccentric (please refer figure b).