The given vertices of the triangle are \( A(0, 4) \), \( B(0, 0) \), and \( C(3, 0) \).
To find the perimeter of the triangle, we calculate the lengths of the three sides using the distance formula:
\[
d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}
\]
First, we calculate the length of \( AB \):
\[
AB = \sqrt{(0 - 0)^2 + (4 - 0)^2} = \sqrt{16} = 4
\]
Then, we calculate the length of \( BC \):
\[
BC = \sqrt{(3 - 0)^2 + (0 - 0)^2} = \sqrt{9} = 3
\]
Finally, we calculate the length of \( AC \):
\[
AC = \sqrt{(3 - 0)^2 + (0 - 4)^2} = \sqrt{9 + 16} = \sqrt{25} = 5
\]
Now, we can calculate the perimeter of the triangle:
\[
\text{Perimeter} = AB + BC + AC = 4 + 3 + 5 = 12
\]