Wait,let me give an example:
suppose you have 70 apples,50 oranges,30 watermelons,30 bananas.Draw a circle graph of your fruit basket.
Total no of fruits:70+50+30+30=180
Now,angle for apples:(70/180)*360=(70*2)=140 degrees
So draw a circle,and from the centre draw an angle of 140 degrees.shade it and mark that apples.

next oranges,degree:(50/180)*360=50*2=100 degrees
next to the orange part of the circle,draw an angle of 100 degrees.Shade it,and mark that oranges

Do the same for the other two:(30/180*360)=(30*2)=60 degrees

This is how you can draw a circlegraph

Hope this helps,
-xC