Answer:
A = π · (r²)
Step-by-step explanation:
π · r² is the area of a circle.
While π · r² · h can also give you the radius, it can only do so for the Volume 
, not the Area 
.
doesn't really apply for a circular object, as it requires the length and width. For circular objects, both are equal to the diameter of the object, and 2² · r² · h does not equal the Volume.
π · r³ seems awfully like the volume of a sphere, but there's something missing. The true volume of a sphere is 
· π · r³, not π · r³.
only applies for triangles.
If a root is a+√b then another is a-√b because of quadatic formula
r2=1-√5
