Class 11

Math

Co-ordinate Geometry

Sets

Let U be the set of all triangles in a plane. If A is the set of all triangles with at least one angle different from $60_{o}$, what is A'?

$A$- Set of triangles with at least one angle different from $60_{0}$ i.e. the set cannot have equilateral triangles

$A_{′}=U−A$

So, $A_{′}$ is the set of all equilateral triangles.