1. The problem statement, all variables and given/known data I am attempting to calculate the approximate time it takes for a stone slab to fully preheat, focusing only on one dimensional steady flow conduction. Both my area and mass are unknown. Thermal conductivity: 6.4 W/mK Specific heat capacity: 0.98 J/gK Density: 2,980 kg/m³ Thickness of slab: 3.18 cm Distance to center: 1.59 cm T1: 260 C. T2 (core): 21.11 C. 2. Relevant equations This is what I'm looking for. 3. The attempt at a solution I've spent hours looking through textbooks trying to find the right equation, but everything I run across seems to have additional info such as area and mass.