Respuesta :

Replace S with the given surface area:

2646 = 6x^2

Divide both sides by 6:

x^2 = 2646 / 6

x^2 = 441

Take square root of both sides:

x = √441

x = 21


The answer is D. 21

21

x = 2646 / 6

x = √441

x = 21