He showed understanding towards my explanation.

This pie chart shows the company's sales.

The climate of this region changes according to the season.

This graph shows the transition of the economy.

This chart shows the increase and decrease in sales.

He is an expert in economics.

The theory of directed graphs is a branch of mathematics.

Graph theory is a branch of mathematics that studies mathematical structures called graphs.

Graph theory is a branch of mathematics that studies the structure of networks.

This bar graph shows the sales of each product.