Solution:
(i) { is a triangle in a plane} ⊄ { is a rectangle in the plane}
(ii) { is an equilateral triangle in a plane} ⊂ { is a triangle in the same plane}
Solution:
(i) { is a triangle in a plane} ⊄ { is a rectangle in the plane}
(ii) { is an equilateral triangle in a plane} ⊂ { is a triangle in the same plane}