Answer
$V$ = $\frac{1}{6}abc$
Work Step by Step
line c to a is given equation
$\frac{z}{c}+\frac{x}{a}$ = $1$
$z$ = $c(1-\frac{x}{a})$
line b to a is given equation
$\frac{y}{b}+\frac{x}{a}$ = $1$
$y$ = $b(1-\frac{x}{a})$
$V$ = $\int_0^{a}\frac{1}{2}bc(1-\frac{x}{a})^{2}dx$
$V$ = $-\frac{1}{6}abc(1-\frac{x}{a})^{3}|_0^a$
$V$ = $\frac{1}{6}abc$