I 15. Find the coordinates of D, the midpoint of AB.
16. Find the length of the median CD.
17. Find the coordinates of the centroid. Label this point as G.

Step-by-step explanation:

15)  point D=(3,1)

for AB we can see that there is an exact triangle of 2 and 5

so AD =   =  and 2(AD) = AB

AB = 2*  ( this is an exact answer, leave it with the square root)

16) find CD  length  we know the points at each end so use the distance formula  P1=(-3,4)  P2=(3,1)

Dist. =

Dist. =   =  = 3 ( exact answer leave the square root )

CD = 3

17)  1/3 of the way along CD from D towards C is where the centroid is.. I just happen to know that from doing this too often.  :/

so that mean   *   is the distance from D to the centroid or

also b/c I happen to know.. :/    c = =  off the top of my head I can see that the point (1,2) is our centroid for this object.. they made it really easy  ... okay..  relatively easy. .:D  

Centroid = (1,2)