Triangle Midsegment Theorem
Midsegment
A midsegment of a triangle is a segment that connects the midpoints of two sides of a triangle.
In the figure D is the midpoint of 
and E is the midpoint of 
.
So, 
is a midsegment.
The Triangle Midsegment Theorem
A midsegment connecting two sides of a triangle is parallel to the third side and is half as long.
If AD = DB and AE = EC,
then 
and 
Example :
Find the value of x.
Here P is the midpoint of AB, and Q is the midpoint of BC. So, 
is a midsegment.
Therefore by the Triangle Midsegment Theorem,
Substitute.
The value of x is 3.
