Use Euler's formula to find the missing number.
Vertices:13
Edges:38
Faces:?
17
16
18
20
The missing number is 18.
Euler's formula states that V - E + F = 2, where V is the number of vertices, E is the number of edges, and F is the number of faces.
Plugging in the given values, we have:
13 - 38 + F = 2
Simplifying and solving for F, we get:
F = 38 - 13 + 2 = 27
Therefore, the polyhedron has 27 faces, and the missing number is 18.