Question

The principal diagonal of a cube of edge $a$ is _____________ whereas diagonal of its base is
_____________.

• A. $\sqrt{3}a$
• B. $\sqrt{2}a$

Answer 1

Cube diagonal formula

Principal diagonal is longest diagonal of the cube and it pass via center of cube and face diagonal will lie on any face of the cube.

Filler 1: The diagonal of a cube $=\sqrt{3}a$

Filler 2: The diagonal of the cube's face $=\sqrt{2}a$

Hence, The principal diagonal of a cube of edge $a$ is _$\sqrt{3}a$_ whereas diagonal of its base is
_$\sqrt{2}a$_.