In the rectangle ABCD, the diagonals intersect at the point O, AB = 6, AC = 13cm. find the perimeter of the COD triangle.

Given: rectangle ABCD, diagonal AC = 13 cm, AB = 6 cm, diagonals intersect at point O.
Find: P △ СOD.
According to the properties of a rectangle, its diagonals are equal (AC = BD).
Crossing at point O, the diagonals bisect each other. This means:
OC = OD = AC / 2 = 13/2 = 6.5 (cm).
The opposite sides of the rectangle are equal (AB = CD, BC = AD). So CD = (6 cm).
Now you can find the perimeter △ СOD, which is equal to the sum of all sides △ СOD.
P △ СOD = 6 + 6.5 + 6.5 = 19 (cm).
Answer: The perimeter of the COD triangle is 19 cm.