8/6 20/x the figures are similar find x

The process:

8/6 = 20/x

You would have to cross multiply first.

8  20    6×20= 120
6    x    8×x=8x

Then you rearrange the equation,

120=8x

And you divide by 8 ( because it has the variable next to it)

120÷8=15

So, x=15