Solid has faces that consist of 2 triangles and 3 rectangles. The solid has 9 edges. How many vertices does the solid have?

A.

6 vertices

B.

8 vertices

C.

10 vertices

D.

12 vertices

The formula for this is V+F=E+2 where V is the vertices, F is the faces and E is the edges.

Given that E=9, F=2+3=5 and V=?, the formula is

V+F=E+2

V+F-F=E+2-F

V=E+2-F

V=9+2-5

V=11-5

V=6

Therefore the vertices are 6.

This method does not apply for all solid shapes.