Answer:
7 mg, 7 centigrams, 7g, 7kg
(x cookies) / (23 students - (12/2) students) = 2 cookies per student
[x / (23 - 6)] cookies per student = 2 cookies per student
23 students * (2 cookies per students) - 12 cookies = x cookies
The "students" unit cancels
46 cookies - 12 cookies = x cookies
x cookies = 34 cookies
A dilation is the best answer. A dilation shrinks or expands the shape on a plane. But now, that shape is the same shape, but a different size.
Congratulations! You have discovered simillar figures. They are the same shape, but different sizes, so they are not congruent.
Hope this helps