Question

If A is set of equilateral triangles then A’ is ________

(a) set of isosceles triangles

(b) set of scalene triangles

(c) union of sets of scalene and isosceles triangles

(d) intersection of sets of scalene and isosceles triangles

I got this question by my school teacher while I was bunking the class.

My enquiry is from Complement of a Set in division Sets of Mathematics – Class 11

Answer 1

The correct answer is (c) union of sets of scalene and isosceles triangles

Explanation: A is set of equilateral triangles i.e. triangles with all three sides equal.

Therefore, A’ is set of triangles with at least one side different i.e. may be all sides different or two sides equal so, A’ is union of sets of scalene and isosceles triangles.