for what are bar graphs and pictographs used??

Dear Student!

Here are the links for the answer to your query.

https://www.meritnation.com/ask-answer/question/what-is-use-of-bar-graph-asked-by-sandeep/data-representation/1417920

https://www.meritnation.com/ask-answer/question/what-is-the-need-of-a-pictograph/data-handling/595784

Cheers!