Question

Make correct statements by filling in the symbols $\subset$ or $\subset ̸$ in the blank space
$\{x:xisaequilateraltriangleinaplane\}....\{x:xisarectangleinasameplane\}$

Answer 1

x:xis a equilateral triangle in a plane}⊄{x:x is a rectangle in a same plane}{x:xis a equilateral triangle in a plane}⊄{x:x is a rectangle in a same plane}
∵∵ every equilatera; triangle in a plane is a triangle in the same plane.