Answer:
1. B 15
2. C Hexagon
Explanation:
1.
Euler's formula tells you the relation between numbers of faces, vertices, and edges of a polyhedron is ...
F +V = E +2
Solving for the number of faces, we have ...
F = E +2 -V
For the given numbers, the missing number is ...
F = 26 +2 -13 = 15
Faces: 15
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2.
The cross section (shaded figure) is described by the number of edges it has. You can count them. There are three pairs of parallel edges, for a total of 6 edges. That makes the figure a hexagon.