Question

Mario`s company makes unusually shaped imitation gemstones. One gemstone had 12 faces and 10 vertices. How many edges did the gemstone have?
A) 23 B) 22 C) 25 D) 20

Answer 1

Believe it or not, there is a formula for this. It's called Euler's Polyhedral Formula.
For E = edges, F = faces, and V = vertices, the formula is
V - E + F = 2

Answer 2

your joking right?

Answer 3

then, it must be option D Edges = 20, because
10 - E + 12 =2
=> 22 - E = 2
=> 22 - 2 + E
=> 20 + E

Answer 4

Because you can`t solve for that because I don not know E

Answer 5

F = 12, V = 10
V - E + F = 2
10 - E + 12 = 2
-E + 22 = 2
-E = -20
E = 20

Answer 6

gotcha

Answer 7

haha, we had F = 12, and V = 10 :)

Answer 8

haha right (: I was trying to subtract both sides instead of adding the 10 and 12...silly me!

Answer 9

@mathstudent55 is a big help! I greatly appreciate it!

Answer 10

wlcm

Answer 11

But, u got it :), yeah he is