P$3.40=10+10+20$

$($a$)$ Determine $\frac{?}{\text{b}\text{a}\text{r}}(y)(mm)$ which locates the centroid $[10]$

$($b$)$ Determine $I_y(m{m}^4)$ for the T$-$beam, and $[10]$

$($c$)$ Determine $I_x(m{m}^4)$ for the T$-$beam $[20]$

SOL $($P$3)[$Note: Use more sheets as needed$]$