In a stress measure mest using straingages, the following strain are measured:

$lo{n}_a=340{10}^{-6},lo{n}_b=315{10}^{-6},lo{n}_c=110{10}^{-6}$

$($a$)$ Find $lo{n}_x,lo{n}_y$ and ${}_{xy}$

$($b$)$ Find principal strains in $2$D$,$ as $lo{n}_1,lo{n}_2,$ and their directions.

$($c$)$ Assuming a steel product, find ${}_1,{}_2.$