$2\mathrm{.}19$ In many applications it is desirable to reduce the weight of a fin without significantly reducing its heat transfer capacity. Compare the heat transfer rate from two straight fins of identical material. The profile of one fin is rectangular while that of the other is triangular Both fins have the same length $L$ and base thickness $.$ Surface heat

$(2\mathrm{.}19)$ transfer is by convection Base temperature is tos. The following data are giveh:

$h=28\frac{w}{m^2}-C,k=186\frac{w}{m}-C$

$L=18cm,b=1cm$