In the given figure the measure of side DC is
In right-angled triangle DBO,
OB2=OD2+BD2
⇒OD2=2O2−122
=400−144 =256
⇒ OD=16 units.
In right angled triangle CAO
OA2=OC2+AC2
⇒ OC2=OA2−AC2
⇒ OC2=202−162
⇒ OC2=400−256 =144
⇒OC=12 units.
Here, DC=OD+OC =16+12 =28 units.