The figure shows what appears to be obtuse triangle A B C with obtuse angle C. Point D is on side A B. Single tick marks pass through segments A D and D B. Point E is on side B C. Double tick marks pass through segments B E and E C. Point F is on side C A. Triple tick marks pass through segments C F and F A. Segment F D is drawn and has length 4. Segment E D is drawn and has length 6.4.