Acube has a surface area of 216 square inches. what is the edge length of the cube?

  6 inches

Step-by-step explanation:

For an edge length of s, the six square faces of the cube add to an area of ...

  cube area = 6s²

Filling in the given information and solving for s, we get

  216 = 6s²

  36 = s² . . . . . divide by 6

  √36 = s = 6 . . . . take the square root

The edge length is 6 inches.

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

3

step-by-step explanation: