The diagonal of the rectangle abcd intersect at the point about cd = 15 cm ac = 20 cm. find the perimeter of the triangle aob.

The perimeter is the sum of all sides. Perimeter of triangle AOD = AO + OD + AD. Let’s find each side.
CD = AB = 15 because in a rectangle the opposite sides are equal. AO and OD are halves of the diagonals AC and AD, respectively. The diagonals in the rectangle are equal to each other, find half of them: 20: 2 = 10. AO = OD = 10.
Perimeter AOD = 15 + 10 + 10 = 35