Ethan has partially filled the prism with 8 unit cubes.

A rectangular prism with length, height, and width of 3.
How many more cubes does he need to fill the prism completely?

A(10
B(15
C(19
D(21

(C)19

Step-by-step explanation:

Volume of the rectangular prism = Length X Height X Width

Volume of the Cube

Number of Cubes that will fill the rectangular prism = Volume of Prism ÷ Volume of Cube

= 27 ÷ 1

=27

Therefore, we would require 27 unit cubes to fill the prism,

Since Ethan has partially filled the prism with 8 unit cubes, the number left to fill the prism = 27-8

=19.

Ethan needs 19 more cubes to fill the rectangular prism.