The ad for this app says that if we have a specific question and can't find it this is the app for that but everything I search nothing I need pops up

Noticice it doesn't say it is a right triangle so don't comment and tell me I'm wrong because it isn't right triangle and also they didn't mentino which was the hyptoonuse if you thought it was a right triangle

 
longest side must be less than the sum of the legnths of the other 2 sides

if we assume that 7 is longest then missing side is x so
3+x>7
minus 3
x>4
whole number to satisfy is
x=5

if we assume the missing side is the largest
3+7>x
10>x
x is 9 at most

if the third side is not the longest side, it can be 5 at minimum
if the third side is the longest side, it can be 9 at max

so the third side can be 5,6,7,8,9 ft