Euler's formula is given by:
C + V = A + 2
Where,
C: number of faces
V: number of vertices
A: number of edges.
Clearing A we have:
A = C + V-2
Substituting values:
A = 21 + 14-2
A = 33
Answer:
the missing number is:
C.33
Answer:
x=10
Step-by-step explanation:
Answer: 
Step-by-step explanation:





Supplements add up to 180°
so just subtract 164 from 180
180
<u>-164
</u> 16
Answer:
r = 7
Step-by-step explanation:
Given
r + 15 = 4r - 6 ( subtract 4r from both sides )
- 3r + 15 = - 6 ( subtract 15 from both sides )
- 3r = - 21 ( divide both sides by - 3 )
r = 7