The sides of are
,
and
.
Using the Triangle Inequality Theorem, the sum of the lengths of any sides of a triangle must be
greater than the length of the remaining side this generates inequalities to examine.
Find the value of .
Consider the inequality is .
Case(i).
\ (First inequality)
(Commutative addition property:
)
(Combine like terms)
(Subtract
from each side)
(Apply additive inverse property:
)
(Subtract
from each side)
(Apply additive inverse property:
)
Case(ii).
\ (Second inequality)
(Commutative addition property:
)
(Combine like terms)
(Subtract
from each side)
(Apply additive inverse property:
)
(Subtract
from each side)
(Apply additive inverse property:
)
(Divide each side by
)
(Cancel common terms)
Case(iii).
\ (Third inequality)
(Commutative addition property:
)
(Combine like terms)
(Subtract
from each side)
(Apply additive inverse property:
)
(Subtract
from each side)
(Apply additive inverse property:
)
(Divide each side by
)
(Cancel common terms)
In order for all conditions to be true,
must be greater than
.
A negative value will always be less than a positive value.