Emily is 12, Samantha is 14, and Lauren is 16. Basically all you do to solve this problem is add numbers that are two apart until you find something.
Ex. 2+4+6=12 4+6+8=18 so on and so forth.
If you use/make a number line, then you will see that the answer is -18 or a. When using a number line, negative = ← and positive = →.
The radius of circle C is also 3 times greater than the radius of circle D.
The area of circle C:
A C = (3r)² π = 9 r² π
The area of circle D:
A D = r² π
9 r² π : r ² π = 9
Answer: It is 9 times the area of circle D.