Need help w/ ratios?

Question

I am having a lot of trouble w/ ratios. Can anyone explain how to do these problems please!

Solve these ratios for X

2:10 :: X:50 X=

9:1000 :: X:4500 X =

Or

Change these ratios to fractions and solve for X

3:12 :: X:48 X=

0.75:300 :: 5 : X X=

And

Changing % to ratios

9%

2.5%

65.52%

If anyone has a simple way to learn these I would appreciate it! Thank you in advance!!!

Answer 1

1.0.45:100::x:1000 and 2. 2.5:200::5:x