Obtain the data to construct a pie chart. For example, use the sales data: $20 million from television sets, $30 million from computers, $35 million from cell phones and $15 million from Internet enabled large screen televisions.
Add the value of each category to find the total and divide each category by this total.
In the example, add all the sales data together to find the total $20 million + $30 million + $35 million + $15 million to obtain $100 million in total sales.
Calculate the percentage of sales for each category by dividing the value by the total. For example, the sales from television sets is 20/100 = 0.2.
Multiply the result by the number of degrees in a circle, 360, to obtain the angle for the individual pie slices.
For example, 0.2 x 360 = 72 degrees. Repeat this step for all remaining categories.
Draw a large circle with your circle template. Circumscribe a square around the circle. Draw in the two diagonals of the square. Call the point where the two diagonals intersect the center of the circle. Draw a horizontal line through the center of the circle such that the endpoints of the line are on the circumference of the circle.
Using a protractor, measure the angle of the first category you want to represent counterclockwise from the horizontal line you drew through the circle. For example, if your pie slice is 72 degrees, mark the point on the circle that corresponds to the 72-degree point on your protractor. Draw a line from the center of the circle to this point. Label this pie slice.
Using your protractor, measure the angle of the next slice of pie counterclockwise from the line you drew in Step 5. Draw a line from the center of the circle to this point. Label this pie slice. Continue in this fashion to construct and label the remaining pie sections.