Question

Can someone teach how to do this?

Answer 1

ANSWER


`\boxed {c. \: \: \: 15}`

EXPLANATION

The number of faces,number of vertices and number of edges that a solid shape has is given by the relation,



`F+V-2=E`

It was given that,

E=38 and F=25.


We substitute these values into the formula to obtain,



`25+V-2=38`

We group similar terms to obtain,



`V = 38 - 25 + 2`


This implies that,


`V = 15`

The correct answer is C.

Answer 2

V = 15

Explanation:

We are given the number of faces and edges and we are to find the number of vertices.

We know the formula that relates the number of faces, number of vertices and the number of edges:

F + V - E = 2

Substituting the given values to find V (number of vertices):

25 + V - 38 = 2

V - 13 = 2

V = 15