use euler’s formula to answer question.
a polyhedrons has 20 vertices and 20 faces. how many edges does it have?
options are
-42
-40
-38
-39

 The correct option is (C) 38.

Step-by-step explanation:  Given that a polyhedron has 20 vertices and 20 faces.

We are to find the number of edges of the polyhedron using Euler's formula.

Euler's formula :

For any polyhedron, the number of vertices and faces together is exactly two more than the number of edges.

Mathematically, V − E + F = 2, where V, E and F represents the number of vertices, number of edges and number of faces of the polyhedron.

For the given polyhedron, we have

number of vertices, V = 20,

number of faces, F = 20

and

number of edges, E = ?

Therefore, from Euler's formula

.

Thus, the required number of edges of the given polyhedron is 38.

Option (C) is CORRECT.

step-by-step explanation:

x^2 -12x + 36 + y^2 = 36

x^2 + y^2 = 12x

r^2 = 12rcos(theta)

r = 12 cos(theta)