There is a trick to measure the area of a circle. In fact, this was a trick people used in the past to find the area under a curve on a graph (before technology gave us better methods).

Misleading Graphs: Displaying a Change in One Variable ... the data are encoded occurs since some make the diameters proportional to the data while others encode the data in the area of the circle.

The graph below is based on 74,476 prices from 3,678 pizza places around the country. ... A pizza is a circle, and the area of a circle increases with the square of the radius.

The area of the square drawn on the hypotenuse is equal to the sum of the squares drawn on the other two sides. , the equation of a circle with radius \(r\) and centre (0, 0) is given by the ...