Name: _______________________
Block: ____ Date: _________
 What are possible side lengths of a triangle?
 How do side lengths relate to angle measures in a triangle?
Triangle Inequality Theorem:
The sum of the side lengths of any 2 sides of a triangle must be ____________
than the length of the third side.
AB  BC  _____
AB  AC  _____
AC  BC  _____
You need to be able to:
a. Figure out if 3 given sides can make a triangle
b. Find possible length of a third side when given 2 sides of a triangle
Example 1:
Solution:
Test the sides and make sure that each pair adds up to a number GREATER THAN
(not equal to!) the third side.
Name: _______________________
Block: ____ Date: _________
Example 2:
Triangle OMG has the following side lengths:
OM = 3 MG = 14
What are the possible lengths for the third side?
Solution:
We can think of lots of side lengths that would work. In fact, because lengths can
have decimals, there are lots and lots (infinite.) Write an INEQUALITY to show
all of the possibilities:
Subtract
2 sides
MG – OM <
x
< length of 3
rd
< MG + OM
______< x < _______
side
<
Add 2
sides
Name: _______________________
Block: ____ Date: _________
Example 3:
You should draw
a picture!