Answer:
Triangle inequality rule states that the sum of eachpair of sides must be greater than the third sides.
240 + 123 > 207 true
240 + 207 > 123 true
123 + 207 > 240 true
A = √(s(s-a)(s-b)(s-c))
s is the semi-perimeter (a + b + c)/2
s = (240 + 123 + 207)/2
s = 285
A = √(285*(285-249)(285-123)(285-207))
A = 12,730 units^2
Step-by-step explanation:
