Question

is this correct ?

Answer 1

Volume is cubic.

Answer 2

first two ratios are correct !
check again the ratio of volumes

Answer 3

use below :
if side lengths are in ratio \(\large \mathbb{\frac{a}{b}}\),

areas will be in ratio : \(\large \mathbb {\frac{a^2}{b^2}}\)

volumes will be in ratio : \(\large \mathbb{\frac{a^3}{b^3}}\)