AB + BC + CD > DA
If the above statement is true, then enter 1 or else enter 0.
In △ABC, we have sum of two sides > third side
=>AB+BC>AC -- (1)
Also, in △ADC, we have sum of two sides > third side
=>DC+AC>AD ---- (2)
Adding equations 1,2 we get
=>AB+BC+CD+AC>AC+AD
=>AB+BC+CD>AD