Answer:
AB = 5 units
Step-by-step explanation:
Calculate the length using the distance formula
d = 
with (x₁, y₁ ) = A(7, 9) and (x₂, y₂ ) = B(3, 12)
AB = 
= 
= 
= 
= 5
Answer:
ST = 12 units
Step-by-step explanation:
As RA is parallel to ET, the angle in R is equal to the angle in T, and the angle in A is equal to the angle in E, so the triangle RAS is similar to the triangle SET.
If RT is 21 units, we have that RS + ST = 21 -> RS = 21 - ST
Using a rule of three with the sides of the triangle (as they are proportional), we have:
RS / ST = AR / ET
(21 - ST) / ST = 6 / 8
4 * (21 - ST) = 3*ST
84 - 4*ST = 3*ST
7*ST = 84
ST = 12 units
The volume of a cube (V) is given in terms of its side length (s) as
... V = s³
You have
... 27n²⁷ = s³
You may recognize that 27 = 3³, so this can be written as

This result matches your second selection
... 3n⁹ units