ABCD ABCD\,ABCD is a right-angled trapezium where AB AB\,AB is parallel to DC DC\,DC and ∠ADC=90∘\angle ADC = 90^\circ∠ADC=90∘.
AB=6AB = 6AB=6 cm, DC=11DC = 11DC=11 cm, and BC=12BC = 12BC=12 cm.
Calculate the length of the diagonal ACACAC.
Give your answer correct to 3 significant figures.