please somebody solve these three problems using pen & paper $($handwritten$),$

$1)$ Find out the section modulus for the following square section $($with octagon hole at the

center$)$ as presented in the Figure $4($b$).$

$2)$ Find out the section modulus for the following triangle section $($with circle hole

at the center$)$ as presented in the figure $(2$b$)$

$3)$ Find out the section modulus for the following square section $($with decagon hole at the

center$)$ as presented in the fimme $(3$ h $)$