Answer:
B
Step-by-step explanation:
Since the cones are similar then the ratio of corresponding sides are equal, that is
[tex]\frac{12}{18}[/tex] = [tex]\frac{h}{45}[/tex] ( h is the height of the smaller cone )
Cross- multiply
18h = 540 ( divide both sides by 18 )
h = 30 cm → B
