ABCD – parallelogram DE-bisector of angle ADC CD = 8cm BE = 12 cm. Find the perimeter.

1. Angle ADE and angle CD are internal crosswise with parallel straight lines BC and AD and secant DE.

2. The bisector DE divides the angle at the vertex D in half, that is, the angle ADE is equal to the angle CDE. The CED angle is equal to the CDE angle, which means that the CDE triangle is isosceles.

3. The CE side is equal to the CD side:

CE = CD = 8 cm.

4. Calculate the length of the aircraft side:

BC = BE + CE = 12 + 8 = 20 cm.

5. Calculate the perimeter of the parallelogram:

2 ВС + 2СD = 2 x 20 + 2 X 8 = 56 cm ^ 2.

Answer: The perimeter of the parallelogram is 56 cm ^ 2.