Question Number 2621 by Yozzi last updated on 23/Nov/15
$${If}\:{you}\:{have}\:{n}\:{non}−{parallel} \\ $$$${lines}\:{in}\:{a}\:{plane},\:{how}\:{many}\:{points} \\ $$$${of}\:{intersection}\:{are}\:{there}? \\ $$
Answered by prakash jain last updated on 23/Nov/15
$$\mathrm{Choose}\:\mathrm{any}\:\mathrm{2}\:\mathrm{lines}\:\mathrm{and}\:\mathrm{we}\:\mathrm{get}\:\mathrm{point}\:\mathrm{of} \\ $$$$\mathrm{intersection}.\:\mathrm{Choosing}\:\mathrm{2}\:\mathrm{lines}\:\mathrm{from}\:{n}=\:^{{n}} {C}_{\mathrm{2}.} \\ $$$$\mathrm{Assuming}\:\mathrm{3}\:\mathrm{or}\:\mathrm{more}\:\mathrm{don}'\mathrm{t}\:\mathrm{have}\:\mathrm{a}\:\mathrm{common} \\ $$$$\mathrm{intersection}\:\mathrm{point}. \\ $$