Q&A for How to Draw a Pie Chart from Percentages

To make a pie chart displaying numbers that are given in decimal form, add all the numbers together, and then divide each individual number by that sum. That will give you more decimal numbers. Multiply each by 100 to arrive at percentages for each number. Multiply each percentage by 360° to get the central angle for each segment of the pie.

In order to convert a percentage to a decimal, simply divide the percentage by 100. For example, 25 percent becomes 0.25 after dividing by 100.

The above article assumes you have been given the percentages, rather than having to find them. If instead you have been given the angles at the center of the pie, you can find the percentages involved by dividing each angle by 360° and then multiplying the resulting decimal number by 100 (and tacking on a % sign).

Don't round off the decimals. Apparently in this case the rounding is causing a discrepancy.

Add together the sales figures of the two companies. Divide the sum by either of the two sales figures. That will give you a decimal number between 0 and 1. convert that to a percentage or a portion of a circle. Use Part 2 above to draw the chart.

Use cross-multiplication to find out how many degrees represent 19.3% of a full, 360° pie chart. Set up this equation: (x / 19.3) = (360 / 100), where x is the number of degrees you're looking for. By cross-multiplying, 100x = (19.3)(360). So 100x = 6,948, and x = 69.48°.

Yes, but graph paper will not be of any particular help in this.

Rounding isn't necessary and could introduce errors if you aren't careful about it. There's a practical limit to how precisely you can draw, and if you draw a 97.2 degree angle the same way you draw a 97.0 one that is fine. But you can't draw either of those exactly, so you may as well think of it as 97.2 since that's what it should be.

Just add the two given numbers and subtract the answer from 100 i.e. 100 minus 65, which is equal to 35 %.