In the diagram, DG = 15, GF = 5, EH = 12, and DE = 8. Triangle D F E is shown. Line segment G H is drawn from side D F to side E F to form triangle G F H. The length of D G is 15, the length of G F is 5, the length of E H is 12, and the length of D E is 8. To prove that △DFE ~ △GFH by the SSS similarity theorem using the information provided in the diagram, it would be enough additional information to know that HF is 2 units and GH is 3 units. HF is 3 units and GH is 2 units. HF is 4 units and GH is 2 units. HF is 3 units and GH is 4 units.