The figure shows how the formula for the circumference of a circle may be used to derive the formula for the AREA of a circle.
A circle labeled C equal to 2-pi-r divided into eight equal sectors. The pieces of the circle were separated from one another and arranged in two rows, with four pieces each labelled 2-pi-r over 2. Pieces are brought together into a parallelogram having a height of r.
Based on the figure, which of the following represents the area of the circle?
A.
A
=
π
r
⋅
r
2
B.
A
=
π
r
⋅
r
C.
A
=
2
π
r
⋅
r
2
D.
A
=
2
π
r
⋅
r