What is the value of x? the triangle is similar.

The ratios between the sides of any two similar triangles are equivalent. You can use that fact to set up an equality between the ratios of the sides on triangle UKL and triangle UWV:

20/12 = 30/(7x - 3)

From there, simply solve for x.

The correct answer will be option- C

Step-by-step explanation:

A research journal is considered as the reliable or credible source of the research as the research articles published in the journal are always verified by the peer-group which includes the scientists.

The peer-group verifies the credibility of the research paper by checking and correcting the steps of the scientific method and checking the eligibility of the collected data and the conclusions drawn from it.

Therefore, Nick should use a medical journal published in 1982 as the credible source for him and thus option- C is the correct answer.