A 6.0-cm-diameter pipe whose surface temperature is maintained at 210C passes through the center of a concrete

Question:

A 6.0-cm-diameter pipe whose surface temperature is maintained at 210ºC passes through the center of a concrete slab 45 cm thick. The outer surface temperatures of the slab are maintained at 15ºC. Using the flux plot, estimate the heat loss from the pipe per unit length. Also work using Table 3-1.