Ten distinct points are identified on the circumference of a circle. How many different convex quadrilaterals can be formed if each vertex must be one of these 10 points?
+118609 trianlges 10C3 = 120
quadrialterals 10C4 = 210
pentagons 10C5 = 252
hexagons 10C6 = 210
heptagons 10C7 = 120
octogons 10C8 = 45
nonogons 10C9 = 10
deacagons 10C10 = 1
120+210+252+210+120+45+10+1 = 968 cyclic polygons
But then the question only wants the quadrilaterals so I get 210
