Write the ratio as a fraction in simplest form 25 to 45

Well first, I can see they are both divisible by 5, so let's divide the denominator and numerator by 5 to get 5/9.

Now look- does 5 and 9 have any common factors? If not, you're done!

Tip: See if both the numerator and denominator have a common factor- and then divide by that factor.

Hope that helped!