Answer:
x = 36
Explanation:
Remark
This can be done as a proportion. A proportion consists of 2 ratios which means it has 4 parts. If you know three of them, you can solve for the 4th.
We can use the following proportion
42/14 = x / 12 Notice that both ratios have tops and bottoms that use corresponding parts. Cross Multiply
14*x = 42 * 12 Combine the right
14x = 504 Divide by 14
x = 504/14
x = 36