Answer:
Perimeter of the triangle formed by connecting the midpoint of the triangle 
Step-by-step explanation:
Here is an image of the triangles.
The Midpoint Theorem: It states that the segment joining two sides of a triangle at the midpoints of those sides is parallel to the third side and is half the length of the third side.
So we have
.
We see that by applying midpoint theorem.



Lets say that 
As perimeter is the summation of the side lengths.
Dividing both sides with 


Now replacing
with
and following the same for the rest.
We will have:
.
So the perimeter of the triangles formed by the midpoints of the triangle 