Answer:
The answer is 30 or 7.5
Step-by-step explanation:
There are two answers because you haven't specified whether the 15 corresponds with the 5 or the 10 so I did both.
If the 15 corresponds with the 5 then the scale factor is 3 because 15 ÷ 5 = 3. To find the unknown amount you have to multiply the 10 by 3 to get 30.
If the 15 corresponds with the 10 then the scale factor is 1.5 because 15 ÷ 10 = 1.5. To find the unknown amount you have to multiply the 5 by 1.5 to get 7.5.
So depending on whether the 15 corresponds to the dimension 5 or 10 you have two answer, you can use the one that applies to you.
