Ratio Introduction:

Part to part

https://www.khanacademy.org/math/pre-algebra/pre-algebra-ratios-rates/pre-algebra-ratios-intro/v/ratios-intro

Part to whole

https://www.khanacademy.org/math/pre-algebra/pre-algebra-ratios-rates/pre-algebra-ratio-word-problems/v/ratios-as-fractions

Example problems

https://www.khanacademy.org/math/pre-algebra/pre-algebra-ratios-rates/pre-algebra-ratios-intro/v/ratio-example-problems

https://www.khanacademy.org/math/pre-algebra/pre-algebra-ratios-rates/pre-algebra-ratio-word-problems/v/ratio-word-problem-exercise-example-1

You can try activities on the left pane also.

Lesson on Ratios:  Click Lessons, then choose ratio.

http://www.learnalberta.ca/content/mesg/html/math6web/index.html?page=home

If you have your textbook read p.177 and try the questions on p. 178-179.