A thermal resistance model of a two-dimensional boundary value problem (BVP) that is commonly found in engineering/experimental heat transfer is presented. The problem consists of two different convectively cooled sub-sections along one boundary, and a heat flux distribution imposed on a portion of another (opposite) boundary, coupled with adiabatic conditions (Neumann boundary conditions) along the remaining boundaries under steady-state conditions. In solving this BVP, the solution technique is highlighted. Consistent with theory, the solution to this problem depends on two Biot numbers, dimensionless heat flux and other dimensionless geometric parameters related to the problem. The present solution is an exact general solution to an existing two-dimensional problem found in literature, and as a special case, the general solution reduces exactly to the existing solution. Also, the present model is validated by comparing the present solution with measured data, and in terms of a temperature difference between two locations on the plate, the analytical solution is well within the experimental error of 0.03 K.