Problema Solution
how many different quadrilaterals can be drawn from 10 coplanar points, where no three of which are collinear
Answer provided by our tutors
We need to find the number of 4-combination of a set of 10 elements:
C(10, 4) = 10!/(4!(10 - 4)!) = (7*8*9*10)/(2*3*4) = 210
Each set of 4 points forms 2 different quadrilaterals therefor:
2*21 = 420
We can make 420 different quadrilaterals.