This thesis is focused on utilizing the combination of giant exoplanet mass via radial velocity observations and radius via transit observations to study their structure and evolution. In Chapter 2, Giant planet thermal evolution models are coupled to tidal evolution dynamics, including orbital evolution and planet interior heating. Viable tidal evolution histories are explored to explain inflated radii of hot Jupiters. Tidal evolution is demonstrated to be a viable heating mechanism in some cases, but for other cases it can not explain the large radii. The thesis continues in Chapter 3 by exhibiting cases when the tidal-thermal evolution model, including energy-limited mass loss, can be used to infer interior properties and demonstrate a possible evolution history. Specifically, I utilize the thermal evolution models to examine planets CoRoT-2b, CoRoT-7b, and the Kepler-11 system. In Chapter 4, planets with lower incident irradiation are examined to infer the heavy element composition inside a range of planets. These planets don't appear to be significantly inflated by the unknown radius inflation mechanism, thus the mysterious mechanism can be ignored. It is shown that the heavy element mass inside these planets correlates with the metallicity of the star. The heavy element mass also correlates with the mass of the planet. However, the heavy element enrichment is inversely related to the mass of the planet. In the final chapter, I develop a mixing equation of state code for the MESA stellar evolution project. This code is developed with the intention of studying inhomogeneous thermal evolution of planets.