The tensile strength and number$-$average molecular weight for two poly$($methyl methacrylate$)$ materials are as follows:

$\backslash$table$[[$Tensile Strength $($MPa$),$Number$-$Average Molecular Weight $($g$/$mol$)],[36,30,000],[160,50,000]]$

Estimate the tensile strength at a number$-$average molecular weight of $39,000\frac{g}{m}ol.$