i want to know why k/(hL2)=3.02 and at/L2^2=3.37

4-59 A cube of aluminum 10cm on each side is initially at a temperature of 300C and is immersed in a fluid at 100C. The heat-transfer coefficient is 900W/m2C. Calculate the temperature at the center of one face after 1min. Obtain the properties of the cube of aluminum with an infinite plate. Thermal conductivity, k=204mCW. Thermal diffusivity =8.42105sm2. Find the parameter L2 Here, is the time and L is the length of the cube. Substitute 8.42105sm2 for ,1min for and cm for L. L2=(5cm1001cmm)28.421051min60mins=2.021 Find the parameter hLk. Here, h is the heat transfer coefficient. Substitute 204mCW for k,900m2CW for h and 0.05m for L. hLk=900(0.05)204=4.53 Find the off center temperature [i0]fromthe graph depicting the axis temperature for an infinite plate in expanded form at hLk=4.53 and L2=2.02 [i0]=0.7 Find the off center temperature [iL] from the graph depicting the axis temperature for an infinite plate in expanded form at hL2k=3.02 and L22=3.37[i0]=0.9