Draw a diagram as shown below.
The diagonals are equal in length. Because AB || DC and AD || BC, the quadrilateral is a square.
Because the diagonals bisect each other at O, therefore
DO = BO = 10.
Likewise,
AO = CO = 10
Because AB = 13, therefore DC = 13.
The perimeter of ΔCOD is CO + CD + DO = 10 + 13 + 10 = 33 in
Answer: 33 in
