Step-by-step explanation:

Answer:
diameter = 4
Step-by-step explanation:
A=pi*r^2
12.566=pi*r^2
3.99988202979=r^2
r=1.99997050723
diameter = 2r
d=2(1.99997050723)
d=3.99994101446 =4
A) 4-4:4+4
=0:8=0
b)4-4:16=0
c)4•4-4:4=15
D)4:4-4+4=1
Answer:
The first one doesn't help while both the second and third helps in finding the vertices
Step-by-step explanation: