Hi. I started with Mathematica and have some troubles.

I need to figure bounded by a given surfaces:

z = 0; z = x; y = 0; y = 4; x = sqrt(25 - y^2)

I try to reproduce that in Mathematica, but makes something wrong and don't understand how to make it right

In documentation I find Plot3D function and try using it.

f[x_, y_] := 0;
g[x_, y_] := x;
h[x_] := 0;
m[x_] := 4;
b[y_] := sqrt (25 - y^2);

Plot3D[{f[x, y], g[x, y], h[x], m[x], b[y]}, {x, 0, 10}, {y, 0, 4}]

And getting something like this:

My friend gave me this image that he made himself by hand, but I'm not sure how much it is correct, and decided to do the same automatically using Mathematica