in a certain circle there are 9 points . what is the number of the triangles connecting 4 points of the 9 points ?
imo : d here we have to select 4 points out of 9 points . order is not important so the answer will be 9 c 4 = 126 answer d
divide(factorial(9), multiply(factorial(divide(const_10, const_2)), factorial(4)))