Uppose, ABCD is the trapezium with AB=60, BC=26,CD=77, DA=25
Through B draw a line parallel to AD to meet DC at E. Clearly ABED is a parallelogram.
So BE=25, EC=DC-DE=17, BC=26
So by Heron's formula we can find the area of BEC and its value will be 204 sq.cm
So the altitude BF through B of BEC will have length 2*204/17=24 cm
So area of ABED is 24*60=1440
So the area of ABCD is 1440+204=1644