Math quiz on circle graphs online. This is an interactive math test online for students in 3rd, 4th, 5th and 6th grades to learn how to interpret circle graphs. Circle graphs are also referred to as pie charts and can be used to represent data visually. Circle graphs show data in the form of ratios or percentages of a 360 degrees circle. In the current quiz, the graph shows proportions of sporting activities students carry out. Questions will be asked based on number and proportion of students carrying out different activities.