Final answer:
Triopas, a member of the Heliadae, seized control of Rhodes, married Hegetoria, and their daughter Cydippe married his brother Cercaphus, who then ruled Rhodes.
Step-by-step explanation:
The man from the Heliadae who seized control of Rhodes and had a daughter named Cydippe with Hegetoria is none other than Triopas. Triopas's brother, Cercaphus, succeeded him and married Cydippe, continuing the family's rule over the island of Rhodes. This lineage and the intermarriage are reminiscent of the complicated dynastic relationships found throughout ancient Greek mythology and history.