Final Answer:
The unknown measurement in the diagram is \(x = 8\) units.
Step-by-step explanation:
In the given diagram, we have two similar triangles, △ABC and △DEF. According to the properties of similar triangles, corresponding angles are equal, and corresponding sides are in proportion. Let's denote the length of side AB as a, BC as b, DE as c, and EF as d.
Now, considering the ratios of corresponding sides, we have:
![\[^AC / ^DF = ^BC / ^EF\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/2822mb9sqfunpvt3xuzbibuc76xpc0nclj.png)
Since the triangles are similar:
![\[^a / ^c = ^b / ^d\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/86uh2pze3925u6oqxoozhxbut2v21xc1os.png)
Now, substitute the known values:
8 / x = 12 / 15
To find x, cross-multiply and solve for x:
8×15 = 12x
120 = 12x
x = 10
However, we need to remember that the question asked for the length of DE, not DC. Since DC is the sum of DE and EC, and EC is given as 2 units, we subtract it from x to find DE:
![\[DE = x - EC = 10 - 2 = 8\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/wvleg94yr5y3n2ekd7g58bx9srcckevr3q.png)
Therefore, the unknown measurement, x, is 8 units.