Given, ABCD is a parallelogram, ABCE is a cyclic quadrilateral and ADC = 52°
To find: The measure of AEC
Here,
(I) ABC = ADC {Being the opposite angles of a parallelogram}
52°
(II) ABC + AEC = 180° {Being opposite angles of a cyclic quardrilateral)
or, 52° + AEC = 180°
or, AEC = 180° - 52°
or, AEC = 128°