What is a ratio?
A ratio has two or more numbers that symbolize relation to each other. Ratios are used to compare the numbers, and you can compare them using division.
First, we need to solve for 42/2.
42/2 = 21
Now, we need to make p/4 equivalent to 21.
21 × 4 = 84
Now, check.
84/4 = 21
Therefore, P = 84.
(You can also just multiply 42/2 by 2 to get 84/4)